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September 19th, 2016 05:00
RAID6 Storage Profile query
I have a query that I would like to discuss
Basically my storage centre 6.5 has a secondary disk pool of 7k 4TB. Due to space issues, I have set the volumes that use this pool to use RAID6 only in their storage profiles.
My understanding was that the Controllers would resize the RAID10 and RAID6 and adjust so that RAID10 was barely used and RAID6 pool would get bigger?
What appears to have happened is that that data that was in RAID10-DM has tiered down to RAID6 but the size of the RAID6 pool has not increased and as a result newer data is writing back into RAID10-DM consuming too much space.
After RAID6 storage profile:
Before RAID6 storage profile:
As you can see when set to use raid 10/raid6 the data didn’t tier down correctly on its own, there would always been a tiny amount tiering and the rest wouldn’t and as a result a lot of data would just site in RAID10-DM consuming excessive space.
rswislocki
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September 22nd, 2016 01:00
Hi,
I confirm that when Compellent allocates disk space for specific RAID Level (for example RAID 10-DM), it never shrinks that space despite the fact, that there is a free space in that RAID level. The same situation as yours I observe in our Compelents. But there is a small difference: we have a plenty of unused, available space in that folder/storage pool and RAID 6-10 has space to expand...
I suggest to contact Copilot - maybe there is a way to shrink particular RAID level space using CLI command....
piedthepiper
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85 Posts
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September 22nd, 2016 05:00
Ah I thought it dynamically allocated them, I shall raise a support request with Dell. it seems silly it cant be adjusted