RAID disk error checking/repair?

Question

We have several PowerVault's with 1+ TB of data on them. They are fileservers configured RAID 5 and need to be up almost 24/7. Recently we have been having some disk errors and also noticed heavy fragmentation. We would like to run chkdsk or a similar program, but are afraid that it will take too long (we can only take the systems off from 3-6 a.m.). How are other people dealing with this problem (fragmentation and errors on RAID)?
David.

Dev Mgr · Answer

One way is to do it regularly (once a month or so), so that fragmentation hasn't become so bad that it takes hours to defragment.

As for the checking of the container (background verify), this takes a certain period of time, but happens in the background, so shouldn't require downtime, but you may notice a slower-than-normal performance while it's happening.

If you want to run a checkdisk/fsck, this will just take a while no matter what with 1 TB virtual drives/containers.

DKP · Answer

What 'disk errors' specifically are you seeing ?   as far as fragmentaton goes that's not a raid, but rather a filesystem level interaction, deframent is the only only solutions obviously.

davidshq · Answer

I am discussing file system level errors (NTFS) as well (the sort that are corrected by chkdsk). David.

tommo666 · Answer

With tb+ arrays, management of the data will be challenging, the chance for soft errors and hard errors increase as the load on the raid cards/arrays increase. You feel like you're constanly firefighting. Putting out the fire as they occur instead of preventing them in the first place.

There are some steps you might try, from Array manager, drill down to the individual disks and view the properties. This should show any errors on the physical disks. It would give you a starting point in your investigations. Make sure the array is at the latest firmware E18. Raid contoller firmware and drivers is always a good bet as well.

I would invest in enterprise level disk tools, like diskeeper. Probably more efficient than the built in version, plus you can schedule defrags.

The first time you run defrag, it will take a long time. After that scheduled defrags will be quicker.

Either way you will have to plan a maintenance period.

pcmeiners · Answer

Running Consistency checks is far more important than your fragmentation worries. As far as fragmentation, third party defraggers provide real time defragging, such as Diskeeper from Executive software.   I do not have Terabyte storage but a chkdsk /f at boot takes about 17 minutes on a 300 gig array (older Perc4 lsi u320-2), with 15k drives , so you should be able to complete yours in the time slot unless your drives and adapter are really slow   Good paper from Intel on raid 6, but read about raid 5 in large array within.   http://www.intel.com/technology/magazine/computing/RAID-6-0505.htm

DPYeilding · Answer

I would uninstall all previous versions of OpenManage from the server and update to the newest version found here:

http://support.dell.com/support/downloads/download.aspx?c=us&cs=555&l=en&s=biz&releaseid=R132111&SystemID=PWE_PNT_XEO_1750&os=WNET&osl=en&deviceid=2331&devlib=0&typecnt=1&vercnt=15&formatcnt=2&libid=36&fileid=178685

If you using the newest version 5.1 of Open Manage with Storage Management, the Open Manage logs will tell you when it begins, completes and if the consistency check fails.

You can manually run a consistency check in Storage Management using these instructions

http://support.dell.com/support/edocs/software/OMSS10UG/vdmgmt.html#323112

or if you save the CLI commands below to a batch file than use Windows Task Scheduler they can be run during off peak hours, which is more beneficial.

Instructions on how to run the CLI Commands using Task Scheduler

Go to a command line and run the following command to display the virtual disks and controllers. You do this because in the batch file you will have to specify the controller and virtual disk you would like to scan.

omreport storage controller to display the controller IDs

omreport storage vdisk controller=ID to display the IDs for the virtual disks attached to the controller.

Once you have the information above you will next open notepad and save the file to the root of C as cons_check.bat or a similar name. You will need to create one for each virtual disk you would like to check.

Inside the file you will add the necessary commands to check the consistency on the selected virtual disk and controller.

Example Syntax

For example, to run a check consistency on virtual disk 4 on controller 1, you would enter the text below into the cons_check.bat file and save it.

omconfig storage vdisk action=checkconsistency controller=1 vdisk=4

Once that is complete you will use the Windows Task Scheduler Wizard to run the batch file during off peak hours.

1. Click the Start button, point to Programs, point to Accessories, and then click Add Scheduled Task.

The Scheduled Task Wizard appears.

2. Click next and follow the onscreen directions. Click Browse and locate the batch file you created above

NOTE: The minimum recommendation for this task is to be run at least once a month

Thank You,

PowerVault

RAID disk error checking/repair?

Was this post helpful?