VERITAS Technical Services has recently discovered a condition under which a striped volume may not perform as designed when using VERITAS Volume Manager (tm) for Windows or VERITAS Storage Foundation (tm) for Windows.

Article:TECH31144  |  Created: 2004-01-16  |  Updated: 2005-01-13  |  Article URL http://www.symantec.com/docs/TECH31144
Article Type
Technical Solution


Environment

Issue



VERITAS Technical Services has recently discovered a condition under which a striped volume may not perform as designed when using VERITAS Volume Manager (tm) for Windows or VERITAS Storage Foundation (tm) for Windows.

Solution



The condition exists only on striped volumes with the following characteristics and only if all of the following conditions are true:  

    1. Striped volumes exist on VERITAS Volume Manager for Windows 2.7, 3.0, or 3.1or on VERITAS Storage Foundation 4.0
2..The striped volume has been extended
3. The striped volume has a length that is greater than the sum of all columns

VERITAS has identified this to be a problem related to the way Volume Manager adjusts to multiples of stripe size on creation,  but adjusts to multiples of stripe unit size when extending. When a striped volume is created, its size is adjusted to multiples of stripe size (128 sectors * # Column). When the volume is extended, the volume size is no longer adjusted to multiples of stripe size, but each column is still kept at multiples of stripe unit size (128 sectors).  

Known symptoms exhibited by such striped volumes are as follows:  
  • The volume will not online after a reboot  
  • The volume will not online after an import operation  
  • The volume cannot be mirrored
While there have not been any reports of data corruption or data loss, the potential for both does exist.

The utility, vxstripe.exe, has been developed to identify striped volumes that are subject to this condition. You can download this utility by clicking on the Download Now link below.

Description of the vxstripe.exe utility:

vxstripe - Validate VERITAS Volume Manager stripe plexes

Usage: vxstripe [-v]
      -v for verbose output

Note: vxstripe scans through the stripe plexes seen by the Volume Manager kernel and reports if they are OK. A stripe plex is considered bad if any of the following conditions are TRUE:
 
1. Volume size of the parent volume is more than the plex size seen as sum of all sub-disk sizes  
2. Plex size seen as sum of all sub-disk sizes is not a multiple of number of columns in the stripe  
3. Column size derived from sum of all sub-disk sizes is not a multiple of stripe width of the stripe plex

Note: Vxstripe.exe will only validate volumes that are online when the utility is run.

Below is an example of the output from vxstripe.exe.

Volume: DynamicGroup\Volume01 Len: 49024(sec)  
Plex: Stripe2-01 Stripe-Width: 128(sec) Len(kernel): 49152(sec)  
#Columns:  3 #Subdisks:  3 Len(all SDs): 49152(sec)  
>>>>>>>>>>Plex IS OK<<<<<<<<<<

Volume: DynamicGroup\Stripe2 Len: 49024(sec)  
Plex: Stripe2-02 Stripe-Width: 128(sec) Len(kernel): 49109(sec)  
#Columns:  3 #Subdisks:  3 Len(all SDs): 49023(sec)  
>>>>>>>>>>Plex IS NOT OK<<<<<<<<<<

This vxstripe utility will identify the condition in the following versions of Volume Manager:  
  • 2.7  
  • 3.0  
  • 3.1  
Additionally, the utility will identify the condition in Storage Foundations 4.0 for Windows.

Should you find you have a volume subject to this condition,  contact VERITAS Technical Services for assistance. The fix for this condition will be incorporated into the next maintenance release (service pack or hotfix) or future version for each affected product.

NOTE: Volume Manager 2.7 Hotfix 08 contains the fix for this issue. Click on the link below for TechFile 268044 to obtain Hotfix 08.

Attachments

vxstripe_266689.exe (54 kBytes)

Supplemental Materials

SourceETrack
Value107900
DescriptionMirroring of a striped volume that has been extended creates a wrong configuration


Legacy ID



266689


Article URL http://www.symantec.com/docs/TECH31144


Terms of use for this information are found in Legal Notices