Sun Storage 3000 Arrays: Smaller Stripesizes May Cause Slow Logical Drive (LD) Rebuild Time

Asset ID:	1-72-1020286.1
Update Date:	2014-03-12
Keywords:

Solution Type Problem Resolution Sure

Solution 1020286.1 : Sun Storage 3000 Arrays: Smaller Stripesizes May Cause Slow Logical Drive (LD) Rebuild Time

Applies to:

Sun Storage 3310 Array - Version Not Applicable and later
Sun Storage 3510 FC Array - Version Not Applicable and later
Sun Storage 3511 SATA Array - Version Not Applicable and later
Sun Storage 3320 SCSI Array - Version Not Applicable and later
All Platforms

Symptoms

After a disk failure in a Sun Storage 3000 Array, the rebuild process may take longer than expected.

This article applies to the following products:

Sun Storage 3310 Array
Sun Storage 3320 Array
Sun Storage 3510 Array
Sun Storage 3511 Array

Cause

One reason that the rebuilds can take a (relatively) long time on logical drives (LDs) in these arrays can be related to the stripesize of the LD. The smaller the stripesize, the longer the rebuild will take.

Solution

For example, we have these two 1.09TB logical drives, each comprised of 4 disks in a RAID5 configuration:

LD    LD-ID        Size Assigned Type   Disks Spare Failed Status
------------------------------------------------------------------------
ld0   0C62738A   1.09TB Primary   RAID5 4     0      0      Good
                         Write-Policy Default          StripeSize 32KB

ld1   09FA2F26   1.09TB Primary   RAID5 4     0      0      Good
                         Write-Policy Default          StripeSize 128KB

One LD has stripesize of 32KB, and the other has a stripesize of 128KB.

When we cause one drive to fail in the LD with the larger (128KB) stripesize, it took this LD approximately 5 hours to rebuild to a hotspare.

When we cause one drive to fail in the LD with the smaller (32KB) stripesize, it took this LD approximately 16 hours to rebuild to a hotspare.

Other factors can influence LD rebuild times, such as the amount of I/O to the array.

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