Monday, June 4, 2012

Potential DS8000 loss of access with VMWare 4.1 and higher with VAAI Zero Blocks/Write Same enabled

Perhaps a little bit out of my league but nevertheless worth mentioning :

Abstract

The extended features of VAAI ( Zero Blocks/Write Same ) are not supported by DS8000 at this time, but are enabled by default on ESX 4.1 or higher.

Content

IBM has received reports of issues when running VAAI Zero Blocks/Write Same commands with DS8000 that have caused application problems including a loss of access to data. Clients are advised to disable VAAI's use of the Zero Blocks/Write Same command to avoid the possibility of an issue, and the procedure to do so is described in the Mitigation information below.

Mitigation

To avoid any issues, use the following to disable the Zero Blocks/Write Same function of VAAI (HardwareAcceleratedInit parameter). Other functions of VAAI may remain enabled for use on other storage systems. All OTHER non VAAI features of VMWare ESX 4.1 or higher are certified with DS8000 (all models) and function normally.

Here's a KB for disabling the Zero Blocks/Write Same command. - http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1033665

Resolution/Support

IBM is working to address the issues of running VAAI Zero Blocks/Write Same functions with DS8000, and will send an update out when this has been done.

1 comment:

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