Hello everyone,
We currently have several ESX clusters sitting on a VMAX array behind VPLEX. We want to keep the clusters on VMAX, but move them out from behind the VPLEX array (direct attach from VMAX).
I am predominantly a Storage Analyst, so forgive me for my ignorance. These are the three (potential) options I see:
My question is, does anyone have experience with #2 or #3? Will either work, or is there a better way?
Any information is appreciated.
Thanks,
Tanner
Hi Depping,
We were going to proceed with testing, but we got some helpful information from the EMC support community. They had the following to say:
"...the VPLEX has its own read cache, so if a volume is written to outside of VPLEX (directly to VMAX) the cache will contain invalid data for those blocks, as the VPLEX would not know they had been updated since the last time they were read from disk, and you could get data corruption."
In light of this point, we have decided to just provision new direct attached VMAX LUNs and vMotion as necessary. As with most shops, we cant take a chance that something gets messed up and we loose data.
Thanks,
Tanner
As I suspected, it looks like option #3 is really out of the picture at this point (cannot take the outage). Still curious if anyone has any experience with scenario #2.
I would simply test this with 1 newly created LUN, present it through VPLEX to the cluster, deploy a VM on it. Now remove it from VPLEX and present it from VMAX and see what happens. My guess is that you will need to register the VM again as it is being seen as a different LUN. But it would be best to discuss this with EMC
Hi Depping,
Assuming we get approval from management, we plan to do exactly that. We have a test cluster that we are going to try the process on. I will post back the results.
Thanks,
Tanner
Hi Depping,
We were going to proceed with testing, but we got some helpful information from the EMC support community. They had the following to say:
"...the VPLEX has its own read cache, so if a volume is written to outside of VPLEX (directly to VMAX) the cache will contain invalid data for those blocks, as the VPLEX would not know they had been updated since the last time they were read from disk, and you could get data corruption."
In light of this point, we have decided to just provision new direct attached VMAX LUNs and vMotion as necessary. As with most shops, we cant take a chance that something gets messed up and we loose data.
Thanks,
Tanner