Uim Cdm Iostat Device Missing Alarm Active

View only the device report only once. $ iostat -d Linux 2.6.31-17-generic (sathiya-laptop) 05/25/10 i686 (1 CPU) Device: tps Blkread/s Blkwrtn/s Blkread Blkwrtn sda 12.17 207.67 1766 707584 sr0 0.00 0.19 0.00 1248 0 View the device report continuously for every 2 seconds, for 5 times. $ iostat -d 2 5 Linux 2.6.31-17-generic. # iostat -xntcz 1 3 tty cpu tin tout us sy wt id 0 5 0 1 0 99 extended device statistics r/s w/s kr/s kw/s wait actv wsvct asvct%w%b device 0.1 0.3 6.1 17.3 0.0 0.0 0.0 20.8 0 0 c8t0d0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0 0 c7t0d0 tty cpu tin tout us sy wt id 0 313 0 62 0 38 extended device statistics r/s w/s kr/s kw/s wait actv wsvct asvct.

Redundant Array of Independent Disks (RAID) is a storage technology that combines multiple disk drive components (typically disk drives or partitions thereof) into a logical unit. Depending on the RAID implementation, this logical unit can be a file system or an additional transparent layer that can hold several partitions. Data is distributed across the drives in one of several ways called #RAID levels, depending on the level of redundancy and performance required. The RAID level chosen can thus prevent data loss in the event of a hard disk failure, increase performance or be a combination of both.

This article explains how to create/manage a software RAID array using mdadm.

• 1RAID levels
• 2Implementation
• 3Installation
  • 3.2Partition the devices
  • 3.6Format the RAID filesystem
    • 3.6.1Calculating the stride and stripe width
• 5Installing Arch Linux on RAID
  • 5.3Configure the boot loader
• 6RAID Maintenance
  • 6.1Scrubbing
• 7Monitoring
• 8Troubleshooting

RAID levels

Despite redundancy implied by most RAID levels, RAID does not guarantee that data is safe. A RAID will not protect data if there is a fire, the computer is stolen or multiple hard drives fail at once. Furthermore, installing a system with RAID is a complex process that may destroy data.

Standard RAID levels

There are many different levels of RAID, please find hereafter the most commonly used ones.

RAID 0

Uses striping to combine disks. Even though it does not provide redundancy, it is still considered RAID. It does, however, provide a big speed benefit. If the speed increase is worth the possibility of data loss (for swap partition for example), choose this RAID level. On a server, RAID 1 and RAID 5 arrays are more appropriate. The size of a RAID 0 array block device is the size of the smallest component partition times the number of component partitions.

RAID 1

The most straightforward RAID level: straight mirroring. As with other RAID levels, it only makes sense if the partitions are on different physical disk drives. If one of those drives fails, the block device provided by the RAID array will continue to function as normal. The example will be using RAID 1 for everything except swap and temporary data. Please note that with a software implementation, the RAID 1 level is the only option for the boot partition, because bootloaders reading the boot partition do not understand RAID, but a RAID 1 component partition can be read as a normal partition. The size of a RAID 1 array block device is the size of the smallest component partition.

RAID 6

Requires 4 or more physical drives, and provides the benefits of RAID 5 but with security against two drive failures. RAID 6 also uses striping, like RAID 5, but stores two distinct parity blocks distributed across each member disk. In the event of a failed disk, these parity blocks are used to reconstruct the data on a replacement disk. RAID 6 can withstand the loss of two member disks. The robustness against unrecoverable read errors is somewhat better, because the array still has parity blocks when rebuilding from a single failed drive. However, given the overhead, RAID 6 is costly and in most settings RAID 10 in far2 layout (see below) provides better speed benefits and robustness, and is therefore preferred.

Nested RAID levels

RAID 1+0

RAID1+0 is a nested RAID that combines two of the standard levels of RAID to gain performance and additional redundancy. It is commonly referred to as RAID10, however, Linux MD RAID10 is slightly different from simple RAID layering, see below.

RAID 10

RAID10 under Linux is built on the concepts of RAID1+0, however, it implements this as a single layer, with multiple possible layouts.

The near X layout on Y disks repeats each chunk X times on Y/2 stripes, but does not need X to divide Y evenly. The chunks are placed on almost the same location on each disk they are mirrored on, hence the name. It can work with any number of disks, starting at 2. Near 2 on 2 disks is equivalent to RAID1, near 2 on 4 disks to RAID1+0.

The far X layout on Y disks is designed to offer striped read performance on a mirrored array. It accomplishes this by dividing each disk in two sections, say front and back, and what is written to disk 1 front is mirrored in disk 2 back, and vice versa. This has the effect of being able to stripe sequential reads, which is where RAID0 and RAID5 get their performance from. The drawback is that sequential writing has a very slight performance penalty because of the distance the disk needs to seek to the other section of the disk to store the mirror. RAID10 in far 2 layout is, however, preferable to layered RAID1+0 and RAID5 whenever read speeds are of concern and availability / redundancy is crucial. However, it is still not a substitute for backups. See the wikipedia page for more information.

RAID level comparison

* Where n is standing for the number of dedicated disks.

Implementation

The RAID devices can be managed in different ways:

• by an abstraction layer (e.g. mdadm);
  Note: This is the method we will use later in this guide.
• by a logical volume manager (e.g. LVM);
• by a component of a file system (e.g. ZFS, Btrfs).

Hardware RAID

The array is directly managed by a dedicated hardware card installed in the PC to which the disks are directly connected. The RAID logic runs on an on-board processor independently of the host processor (CPU). Although this solution is independent of any operating system, the latter requires a driver in order to function properly with the hardware RAID controller. The RAID array can either be configured via an option rom interface or, depending on the manufacturer, with a dedicated application when the OS has been installed. The configuration is transparent for the Linux kernel: it does not see the disks separately.

FakeRAID

This type of RAID is properly called BIOS or Onboard RAID, but is falsely advertised as hardware RAID. The array is managed by pseudo-RAID controllers where the RAID logic is implemented in an option rom or in the firmware itself with a EFI SataDriver (in case of UEFI), but are not full hardware RAID controllers with all RAID features implemented. Therefore, this type of RAID is sometimes called FakeRAID. dmraid from the official repositories, will be used to deal with these controllers. Here are some examples of FakeRAID controllers: Intel Rapid Storage, JMicron JMB36x RAID ROM, AMD RAID, ASMedia 106x, and NVIDIA MediaShield.

Which type of RAID do I have?

Since software RAID is implemented by the user, the type of RAID is easily known to the user.

However, discerning between FakeRAID and true hardware RAID can be more difficult. As stated, manufacturers often incorrectly distinguish these two types of RAID and false advertising is always possible. The best solution in this instance is to run the lspci command and looking through the output to find the RAID controller. Then do a search to see what information can be located about the RAID controller. Hardware RAID controllers appear in this list, but FakeRAID implementations do not. Also, true hardware RAID controller are often rather expensive, so if someone customized the system, then it is very likely that choosing a hardware RAID setup made a very noticeable change in the computer's price.

Installation

Installmdadm. mdadm is used for administering pure software RAID using plain block devices: the underlying hardware does not provide any RAID logic, just a supply of disks. mdadm will work with any collection of block devices. Even if unusual. For example, one can thus make a RAID array from a collection of thumb drives.

Prepare the devices

If the device is being reused or re-purposed from an existing array, erase any old RAID configuration information:

or if a particular partition on a drive is to be deleted:

• Zapping a partition's superblock should not affect the other partitions on the disk.
• Due to the nature of RAID functionality it is very difficult to securely wipe disks fully on a running array. Consider whether it is useful to do so before creating it.

Partition the devices

It is highly recommended to partition the disks to be used in the array. Since most RAID users are selecting disk drives larger than 2 TiB, GPT is required and recommended. See Partitioning for the more information on partitioning and the available partitioning tools.

GUID Partition Table

• After creating the partitions, their partition type GUIDs should be A19D880F-05FC-4D3B-A006-743F0F84911E (it can be assigned by selecting partition type Linux RAID in fdisk or FD00 in gdisk).
• If a larger disk array is employed, consider assigning filesystem labels or partition labels to make it easier to identify an individual disk later.
• Creating partitions that are of the same size on each of the devices is recommended.

Master Boot Record

For those creating partitions on HDDs with a MBR partition table, the partition types IDs available for use are:

• 0xFD for raid autodetect arrays (Linux raid autodetect in fdisk)
• 0xDA for non-fs data (Non-FS data in fdisk)

See Linux Raid Wiki:Partition Types for more information.

Build the array

Use mdadm to build the array. See mdadm(8) for supported options. Several examples are given below.

• If this is a RAID1 array which is intended to boot from Syslinux a limitation in syslinux v4.07 requires the metadata value to be 1.0 rather than the default of 1.2.
• When creating an array from Arch installation medium use the option --homehost=myhostname (or --homehost=any to always have the same name regardless of the host) to set the hostname, otherwise the hostname archiso will be written in the array metadata.

The following example shows building a 2-device RAID1 array:

The following example shows building a RAID5 array with 4 active devices and 1 spare device:

The following example shows building a RAID10,far2 array with 2 devices:

The array is created under the virtual device /dev/mdX, assembled and ready to use (in degraded mode). One can directly start using it while mdadm resyncs the array in the background. It can take a long time to restore parity. Check the progress with:

Update configuration file

By default, most of mdadm.conf is commented out, and it contains just the following:

This directive tells mdadm to examine the devices referenced by /proc/partitions and assemble as many arrays as possible. This is fine if you really do want to start all available arrays and are confident that no unexpected superblocks will be found (such as after installing a new storage device). A more precise approach is to explicitly add the arrays to /etc/mdadm.conf:

This results in something like the following:

This also causes mdadm to examine the devices referenced by /proc/partitions. However, only devices that have superblocks with a UUID of 27664… are assembled in to active arrays.

See mdadm.conf(5) for more information.

Assemble the array

Once the configuration file has been updated the array can be assembled using mdadm:

Format the RAID filesystem

The array can now be formatted with a file system like any other partition, just keep in mind that:

• Due to the large volume size not all filesystems are suited (see: Wikipedia:Comparison of file systems#Limits).
• The filesystem should support growing and shrinking while online (see: Wikipedia:Comparison of file systems#Features).
• One should calculate the correct stride and stripe-width for optimal performance.

Calculating the stride and stripe width

Two parameters are required to optimise the filesystem structure to fit optimally within the underlying RAID structure: the stride and stripe width. These are derived from the RAID chunk size, the filesystem block size, and the number of 'data disks'.

The chunk size is a property of the RAID array, decided at the time of its creation. mdadm's current default is 512 KiB. It can be found with mdadm:

The block size is a property of the filesystem, decided at its creation. The default for many filesystems, including ext4, is 4 KiB. See /etc/mke2fs.conf for details on ext4.

The number of 'data disks' is the minimum number of devices in the array required to completely rebuild it without data loss. For example, this is N for a raid0 array of N devices and N-1 for raid5.

Once you have these three quantities, the stride and the stripe width can be calculated using the following formulas:

Example 1. RAID0

Example formatting to ext4 with the correct stripe width and stride:

• Hypothetical RAID0 array is composed of 2 physical disks.
• Chunk size is 64 KiB.
• Block size is 4 KiB.

stride = chunk size / block size. In this example, the math is 64/4 so the stride = 16.

stripe width = # of physical data disks * stride. In this example, the math is 2*16 so the stripe width = 32.

Example 2. RAID5

Example formatting to ext4 with the correct stripe width and stride:

• Hypothetical RAID5 array is composed of 4 physical disks; 3 data discs and 1 parity disc.
• Chunk size is 512 KiB.
• Block size is 4 KiB.

stride = chunk size / block size. In this example, the math is 512/4 so the stride = 128.

stripe width = # of physical data disks * stride. In this example, the math is 3*128 so the stripe width = 384.

Theatre of war 2 license key west. For more on stride and stripe width, see: RAID Math.

Example 3. RAID10,far2

Example formatting to ext4 with the correct stripe width and stride:

• Hypothetical RAID10 array is composed of 2 physical disks. Because of the properties of RAID10 in far2 layout, both count as data disks.
• Chunk size is 512 KiB.

• Block size is 4 KiB.

stride = chunk size / block size.In this example, the math is 512/4 so the stride = 128.

stripe width = # of physical data disks * stride.In this example, the math is 2*128 so the stripe width = 256.

Mounting from a Live CD

Users wanting to mount the RAID partition from a Live CD, use:

If your RAID 1 that is missing a disk array was wrongly auto-detected as RAID 1 (as per mdadm --detail /dev/md<number>) and reported as inactive (as per cat /proc/mdstat), stop the array first:

Installing Arch Linux on RAID

You should create the RAID array between the Partitioning and formatting steps of the Installation Procedure. Instead of directly formatting a partition to be your root file system, it will be created on a RAID array.Follow the section #Installation to create the RAID array. Then continue with the installation procedure until the pacstrap step is completed.When using UEFI boot, also read EFI system partition#ESP on software RAID1.

Update configuration file

After the base system is installed the default configuration file, mdadm.conf, must be updated like so:

Always check the mdadm.conf configuration file using a text editor after running this command to ensure that its contents look reasonable.

Continue with the installation procedure until you reach the step Installation guide#Initramfs, then follow the next section.

Configure mkinitcpio

Add mdadm_udev to the HOOKS section of the mkinitcpio.conf to add support for mdadm into the initramfs image:

If you use the mdadm_udev hook with a FakeRAID array, it is recommended to include mdmon in the BINARIES array:

Then Regenerate the initramfs.

See also mkinitcpio#Using RAID.

Configure the boot loader

Root device

Point the root parameter to the mapped device. E.g.:

If booting from a software raid partition fails using the kernel device node method above, an alternative way is to use one of the methods from Persistent block device naming, for example:

See also GRUB#RAID.

RAID0 layout

Since version 5.3.4 of the Linux kernel, you need to explicitly tell the kernel which RAID0 layout should be used: RAID0_ORIG_LAYOUT (1) or RAID0_ALT_MULTIZONE_LAYOUT (2).[1] You can do this by providing the kernel parameter as follows:

The correct value depends upon the kernel version that was used to create the raid array: use 1 if created using kernel 3.14 or earlier, use 2 if using a more recent version of the kernel. One way to check this is to look at the creation time of the raid array:

Here we can see that this raid array was created on September 24, 2015. The release date of Linux Kernel 3.14 was March 30, 2014, and as such this raid array is most likely created using a multizone layout (2).

RAID Maintenance

Scrubbing

It is good practice to regularly run data scrubbing to check for and fix errors. Depending on the size/configuration of the array, a scrub may take multiple hours to complete.

To initiate a data scrub:

The check operation scans the drives for bad sectors and automatically repairs them. If it finds good sectors that contain bad data (the data in a sector does not agree with what the data from another disk indicates that it should be, for example the parity block + the other data blocks would cause us to think that this data block is incorrect), then no action is taken, but the event is logged (see below). This 'do nothing' allows admins to inspect the data in the sector and the data that would be produced by rebuilding the sectors from redundant information and pick the correct data to keep.

As with many tasks/items relating to mdadm, the status of the scrub can be queried by reading /proc/mdstat.

Example:

To stop a currently running data scrub safely:

When the scrub is complete, admins may check how many blocks (if any) have been flagged as bad:

General notes on scrubbing

It is a good idea to set up a cron job as root to schedule a periodic scrub. See raid-check^AUR which can assist with this. To perform a periodic scrub using systemd timers instead of cron, See raid-check-systemd^AUR which contains the same script along with associated systemd timer unit files.

RAID1 and RAID10 notes on scrubbing

Due to the fact that RAID1 and RAID10 writes in the kernel are unbuffered, an array can have non-0 mismatch counts even when the array is healthy. These non-0 counts will only exist in transient data areas where they do not pose a problem. However, we cannot tell the difference between a non-0 count that is just in transient data or a non-0 count that signifies a real problem. This fact is a source of false positives for RAID1 and RAID10 arrays. It is however still recommended to scrub regularly in order to catch and correct any bad sectors that might be present in the devices.

Removing devices from an array

One can remove a device from the array after marking it as faulty:

Now remove it from the array:

Remove device permanently (for example, to use it individually from now on):Issue the two commands described above then:

• Do not issue this command on linear or RAID0 arrays or data loss will occur!
• Reusing the removed disk without zeroing the superblock will cause loss of all data on the next boot. (After mdadm will try to use it as the part of the raid array).

Stop using an array:

1. Umount target array
2. Stop the array with: mdadm --stop /dev/md0
3. Repeat the three command described in the beginning of this section on each device.
4. Remove the corresponding line from /etc/mdadm.conf.

Adding a new device to an array

Adding new devices with mdadm can be done on a running system with the devices mounted.Partition the new device using the same layout as one of those already in the arrays as discussed above.

Assemble the RAID array if it is not already assembled:

Add the new device the array:

This should not take long for mdadm to do.

Depending on the type of RAID (for example, with RAID1), mdadm may add the device as a spare without syncing data to it. You can increase the number of disks the RAID uses by using --grow with the --raid-devices option. For example, to increase an array to four disks:

You can check the progress with:

Check that the device has been added with the command:

This is because the above commands will add the new disk as a 'spare' but RAID0 does not have spares. If you want to add a device to a RAID0 array, you need to 'grow' and 'add' in the same command, as demonstrated below:

Increasing size of a RAID volume

If larger disks are installed in a RAID array or partition size has been increased, it may be desirable to increase the size of the RAID volume to fill the larger available space. This process may be begun by first following the above sections pertaining to replacing disks. Once the RAID volume has been rebuilt onto the larger disks it must be 'grown' to fill the space.

Next, partitions present on the RAID volume /dev/md0 may need to be resized. See Partitioning for details. Finally, the filesystem on the above mentioned partition will need to be resized. If partitioning was performed with gparted this will be done automatically. If other tools were used, unmount and then resize the filesystem manually.

Change sync speed limits

Syncing can take a while. If the machine is not needed for other tasks the speed limit can be increased.

Check the current speed limit.

Increase the limits.

Then check out the syncing speed and estimated finish time.

See also sysctl#MDADM.

RAID5 performance

To improve RAID5 performance for fast storage (e.g. NVMe), increase /sys/block/mdx/md/group_thread_cnt to more threads. For example, to use 8 threads to operate on a RAID5 device:

See git kernel commit 851c30c9badf.

Monitoring

A simple one-liner that prints out the status of the RAID devices:

Watch mdstat

Or preferably using tmux

Track IO with iotop

The iotop package displays the input/output stats for processes. Use this command to view the IO for raid threads.

Track IO with iostat

The iostat utility from sysstat package displays the input/output statistics for devices and partitions.

Mailing on events

A mail transer agent is required to accomplish this. Perhaps the most simplistic solution is to use dma which is very tiny (installs to 0.08 MiB) and requires no setup.

Edit /etc/mdadm.conf defining the email address to which notifications will be received.

To test the configuration:

The factual accuracy of this article or section is disputed.

mdadm includes mdmonitor.service to perform the monitoring task, so at this point, you have nothing left to do. If you do not set a mail address in /etc/mdadm.conf, that service will fail. If you do not want to receive mail on mdadm events, the failure can be ignored; if you do not want notifications and are sensitive about failure messages, you can mask the unit.

Troubleshooting

If you are getting error when you reboot about 'invalid raid superblock magic' and you have additional hard drives other than the ones you installed to, check that your hard drive order is correct. During installation, your RAID devices may be hdd, hde and hdf, but during boot they may be hda, hdb and hdc. Adjust your kernel line accordingly. This is what happened to me anyway.

Error: 'kernel: ataX.00: revalidation failed'

If you suddenly (after reboot, changed BIOS settings) experience Error messages like:

Is does not necessarily mean that a drive is broken. You often find panic links on the web which go for the worst. In a word, No Panic. Maybe you just changed APIC or ACPI settings within your BIOS or Kernel parameters somehow. Change them back and you should be fine. Ordinarily, turning ACPI and/orACPI off should help.

Right click or press and hold on the taskbar. Click tap on Lock all taskbars (if you have multiple displays) or lock the taskbar (if you have single display) to check (lock) or uncheck (unlock) for what you want. How to unlock toolbar in word. Lock or Unlock the taskbar with Settings Open the Settings app. Navigate to Personalization - Taskbar. On the right, enable the Lock the taskbar toggle option to lock the taskbar. Disabling this option will unlock the taskbar.

Start arrays read-only

When an md array is started, the superblock will be written, and resync may begin. To start read-only set the kernel module md_mod parameter start_ro. When this is set, new arrays get an 'auto-ro' mode, which disables all internal io (superblock updates, resync, recovery) and is automatically switched to 'rw' when the first write request arrives.

To set the parameter at boot, add md_mod.start_ro=1 to your kernel line.

Or set it at module load time from /etc/modprobe.d/ file or from directly from /sys/:

Recovering from a broken or missing drive in the raid

You might get the above mentioned error also when one of the drives breaks for whatever reason. In that case you will have to force the raid to still turn on even with one disk short. Type this (change where needed):

Now you should be able to mount it again with something like this (if you had it in fstab):

Now the raid should be working again and available to use, however with one disk short! So, to add that one disc partition it the way like described above in #Prepare the devices. Once that is done you can add the new disk to the raid by doing:

If you type:

you probably see that the raid is now active and rebuilding.

You also might want to update your configuration (see: #Update configuration file).

Benchmarking

There are several tools for benchmarking a RAID. The most notable improvement is the speed increase when multiple threads are reading from the same RAID volume.

tiobench^{AUR[broken link: package not found]} specifically benchmarks these performance improvements by measuring fully-threaded I/O on the disk.

bonnie++ tests database type access to one or more files, and creation, reading, and deleting of small files which can simulate the usage of programs such as Squid, INN, or Maildir format e-mail. The enclosed ZCAV program tests the performance of different zones of a hard drive without writing any data to the disk.

hdparm should not be used to benchmark a RAID, because it provides very inconsistent results.

See also

• Linux Software RAID (thomas-krenn.com)
• Linux RAID wiki entry on The Linux Kernel Archives
• Chapter 15: Redundant Array of Independent Disks (RAID) of Red Hat Enterprise Linux 6 Documentation
• Linux-RAID FAQ on the Linux Documentation Project
• BAARF(Archive.org) including Why should I not use RAID 5?(Archive.org) by Art S. Kagel
• Introduction to RAID, Nested-RAID: RAID-5 and RAID-6 Based Configurations, Intro to Nested-RAID: RAID-01 and RAID-10, and Nested-RAID: The Triple Lindy in Linux Magazine

mailing list

mdadm

• Software RAID on Linux with mdadm in Linux Magazine

Forum threads

Iostat is one of the most useful command when troubleshooting a disk I/O performance issue. It can also be used to troubleshoot a CPU performance issue as well. The iostat command can be run in various ways.

Summary since boot

By default if you run iostat without any options it will show the summary since boot which is very useful to compare the system performance in a bottleneck vs average system performance.
Example 1

The output shows all the device instances as well as terminal and cpu statistics. Below are the parameter being displayed :

Current statistics

The current disk I/O statistics need to be analyzed, which can be done by running iostat over some period of time. The syntax to run iostat at some interval with some optional count is :

Example 2
To run iostat at 1 seconds interval with a count of 5 :

Display Only disk statistics

Classic style
The default iostat also shows the CPU statistics. To display only the disk statistics use the -d otion. This would print disk statistics in a classic way with kps, tps and serv values.

Example 3

I actually have 5 disks in my system, but the above output only shows disk statistics for 4 disk only. That’s because the default iostat command shows disk statistics only for first 4 disks. To print disk statistics for more than 4 disk we can use -l option ( we can provide number of disks for which we want disk statistics with l )

Example 4

In the example above 5 is number of disk to print the statistics for and (1 3) is the interval and count respectively.

New style
In the latest style of iostat command with option -D, we get rps (reads per second), wps (write per second), and util (% utilization).

Example 5

Statistics for a specific disk(s)

We can also get disk I/O statistics only for a specific disk or set of disk using iostat :

Example 6

Remember to limit the disks shown in output with l, otherwise it would print all disk anyways.

To print logical disk names

Most of the times we understand logical disk names. So to print disk I/O statistics using the logical disk names use the option -n :

Example 7

Extended Device statistics

The option -x displays the extended device statistics.

Example 8

The extended statistics shows some extra info such as reads/sec (r/s), writes/sec (w/s), kilobytes read and kilobytes write per sec (kr/s and kw/s), avg. active transactions (actv), average service time (svc_t) etc.

Per partition statistics

with the -p option we can also print the per partition io statistics if we want.

Example 9

Error Statistics

To check for hard and soft errors on disk use the -e option with iostat command :
Example 10

The various errors are :

The various errors statistics can also be displayed with -E option :

Example 11

Combining multiple options

Now when using iostat, we usually combine 3 or 4 options to give you only the output in which we are interested. As show in below example we would only get non-zero lines, with logical disk name, extended statistics etc by combining various options in iostat example.

Example 12