Checking a Logical Drive's Physical Drives for Errors (Consistency Check)

For logical drives that use RAID level 1, 3, or 5, you can check their physical drives for parity and mirror errors by doing a consistency check.

Consistency checks are very important because they can detect and correct parity errors or bad disk blocks. A consistency check forces every block on a physical drive to be read, and any bad blocks are marked; those blocks are not used again. This is critical because a bad disk block can prevent a disk rebuild from completing. We strongly recommend that you run consistency checks on a regular basis—at least once per week. Note that consistency checks degrade performance, so you should run them when the system load can tolerate it.

You use IRM or the irconcheck utility to run consistency checks.




	TIP: You can set up a `cron` job to run `irconcheck` regularly; you cannot do that with IRM.

IRM is described below. irconcheck is described in “Using irconcheck”.

Using IRM

You can use IRM to do a consistency check on one logical drive or on multiple drives. Each of these methods is described in this section.

One Logical Drive

This section describes the steps for using IRM to check the consistency of one logical drive. Note that these steps assume you have started IRM and (if applicable) selected the HP RAID 4Si controller the logical drive is configured on.

Menu path: "Management Menu" → Objects → Logical Drive

The "Logical Drives" menu displays.

On the "Logical Drives" menu, select the drive you want to check. The "Logical Drive n" menu displays.
Select Check Consistency. You are asked to confirm that you want to check the consistency of the selected drive.
If you do not want to do the consistency check, select NO. You are placed back in the "Logical Drive n" menu; go to step 6.
If you want to do the consistency check, select YES; go to step 4.
NOTE: The consistency check of a large logical drive can take more than 2 hours.

The consistency check starts, and a screen (titled "Check Consistency Progress") displays. The screen contains a horizontal bar that grows to show the progress of the consistency check.




	TIP: Once the consistency check starts, you can abort it if you want/need to: press Esc. A warning message displays; press any key to continue. Note that this does not continue the abort, but just places you in a confirmation dialog box. Then, if you do not want to abort the consistency check, select `NO`; the check continues (go to step 5). If you want to abort the consistency check, select `YES`. The check stops; press any key to continue. You are placed back in the "Logical Drives" menu; go to step 7.

When the consistency check finishes, press any key to remove the progress display; you are placed back in the "Logical Drive n" menu.
Press Esc; you are placed in the "Logical Drives" menu.
Press Esc; you are placed in the "Objects" menu.
Press Esc; you are placed in the "Management Menu."
Press Esc. An exit confirmation dialog box displays.
Highlight YES and press Enter; IRM ends.

Multiple Logical Drives

This section describes the steps for using IRM to check the consistency of one or more logical drives. Note that these steps assume you have started IRM and (if applicable) selected the HP RAID 4Si controller the logical drive is configured on.

Menu path: "Management Menu" → Check Consistency

The "Logical Drives Configured" screen, with the "Logical Drives" menu to the bottom left, displays. You are placed in the "Logical Drives" menu.

For each logical drive you want checked, use the up and down arrow keys to highlight the drive and then press the spacebar to select it. If you want to unselect a drive that is already selected, highlight it and press the spacebar. An asterisk (*) appears to the left of each selected drive.
TIP: If you want to select or unselect all of the drives listed, press F2 (which serves as a toggle between selecting all drives and unselecting all drives).
When you have selected all of the drives you want to check, press F10.You are asked to confirm that you want to check the consistency of the selected drives.
If you do not want to do the consistency check, select NO. You are placed back in the "Logical Drives" menu; note that all of the logical disks have been unselected. Go to step 6.
If you want to do the consistency check, select YES; go to step 4.
NOTE: The consistency check of a large logical drive can take more than 2 hours.

The consistency check starts, and a screen (titled "Check Consistency Progress") displays. The screen contains a horizontal bar for each logical drive being checked. The horizontal bar for each drive grows to show the progress of the consistency check on that drive.




	TIP: Once the consistency check starts, you can abort it if you want/need to: press Esc. A warning message displays; press any key to continue. Note that this does not continue the abort, but just places you in a confirmation dialog box. Then, if you do not want to abort the consistency check, select `NO`; the check continues (go to step 5). If you want to abort the consistency check, select `YES`. The check stops; press any key to continue. You are placed back in the "Logical Drives" menu; go to step 6.

When the consistency check finishes, press any key to remove the progress display; you are placed back in the "Logical Drives" menu.
Press Esc; you are placed in the "Management Menu."
Press Esc. An exit confirmation dialog box displays.
Highlight YES and press Enter; IRM ends.

Using irconcheck

You can use irconcheck from the HP-UX command line or set up a cron job to run it at a regular time. Each of these methods is described in this section. See the irconcheck(1M) man page for details (including the messages irconcheck generates).

Command Line

This section describes how to use irconcheck from the HP-UX command line to do a consistency check on one or more logical drives. Note that when you run irconcheck from the command line, the messages are sent to your (the user's) console.

If you include /opt/raid4si/bin in your PATH statement, you can run the command as it is shown below. Otherwise, you must include /opt/raid4si/bin as part of the command name (that is, /opt/raid4si/bin/irconcheck).

You must be logged in as root to run this command.

The syntax is as follows:

irconcheck [-d device_file -l logical_drive_number]
           [-d device_file -a -l logical_drive_number]
           [-d device_file -q]

Note that some of the lines in the above syntax are indented for readability purposes only. When you actually type the command, you do not have to indent anything.

The command parameters are as follows:

d device_file specifies the HP RAID 4Si controller the logical drive is configured for.
l logical_drive_number specifies the logical drive you want to check.
a specifies that you want to abort the consistency check being run on the specified logical drive.
q specifies that you want to display the progress of the consistency check being run. If no consistency check is running, the status of the last successfully completed check is displayed.

If you do not specify any of the above options, a consistency check is run on all logical drives that are on each HP RAID 4Si controller installed in the HP-UX system. Note that because it can take several hours, we recommend doing this kind of check through a cron job that runs it regularly at a time when the system load is low.

Examples of irconcheck

Some examples of using irconcheck are shown below.

Example 1
If you want to start a consistency check on logical drive 0 on the controller at /dev/iop0, issue this command:
irconcheck -d /dev/iop0 -l 0
Example 2
If you want to check the progress of the consistency check running on the controller at /dev/iop0, issue this command:
irconcheck -d /dev/iop0 -q
Example 3
If you want to abort the consistency check running on logical drive 0 on the controller at /dev/iop0, issue this command:
irconcheck -d /dev/iop0 -a -l 0
Example 4
If you want to run a consistency check on all logical drives on each controller installed in the system, issue this command:
irconcheck
Remember, this kind of check can take several hours, so we recommend using a cron job (to run it regularly at a low system load time) instead.

Through a cron Job

When you run irconcheck through a cron job, you cannot specify any of the irconcheck options. This means it does a consistency check on all logical drives on each HP RAID 4Si controller in the system. So, the check can run for several hours. Also, when you run irconcheck through a cron job, the messages are written to the /var/adm/syslog/syslog.log system log file.

Here is an example of an entry for a cron job:

# Run a consistency check weekly on all logical drives on all
# HP RAID 4Si controllers in the system.
#
# Minute    Hour   MonthDay  Month  Weekday   Command
#----------------------------------------------------------
    00      22        *        *       6      /opt/raid4si/bin/irconcheck

This entry will run irconcheck (without any options) once every week, on Saturday (Weekday = 6), at 10:00 p.m. (Hour [22], Minute [00]= 22:00). Note that in the above example, lines beginning with a pound sign (#) are standard HP-UX comment lines; the sixth line (shown in bold, for highlighting purposes) is the one that is actually executed by the cron job.

You can create cron entries in two ways:

Using the crontab command. See the cron(1M) and crontab(1) man pages for details about creating cron jobs and the necessary entries.
Using SAM. Follow the menu path Process Management → Scheduled Cron Jobs → Action → Add. Then, SAM prompts you for the parameters (time, the command to run, and frequency) and creates the corresponding cron entry.

Checking a Logical Drive's Physical Drives for Errors (Consistency Check)

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