Enabling CRC Checksum on Synology for ESXi

Martin Tarlink
Martin Tarlink used Ask the Experts™
on
Hi
What do you think about enabling CRC Checksum on Synology NAS that works as iSCSI Target for VMware ESXi host?

I have two options
[_] Header digest
[_] Data Digest

I can't find on google if it is recommended to have it ON, or have it enabled could lead to some issues?
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AbhilashBlogger

Commented:
May i ask what is the reason to enable the CRC Checksum?
Martin TarlinkNetwork Systems Administrator

Author

Commented:
I do not have a reason that why I ask  here if anyone use if and for what purpose.

I test it already and the moment I enabled it ESXi lost connection with iSCSI Target.
Blogger
Commented:
Its basically for high resiliency. This will enable iSCSI Initiator and Target to conduct CRC bit checking.
It is for those environments that cannot tolerate errors.
It should not cause any issues if you enable it but one of very old VMware KB Articles suggests that if data digest id enabled on iSCSI the Windows machines may not work well.
Refer the below KB. Not sure if it has changed
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1003043

Also this will cause a high usage of CPU on NAS. If you don't have a reason i would suggest you not to enable it. Or may be you could try. But since you said its causing issues you better not mess around with it.

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