FAS and V-Series Storage Systems Discussions

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Re: OK to convert a Flash Pool from RAID-DP to RAID4?

As far as I know, the only way to disable low spare warning, is by setting the "raid.min_spare_count" option to zero. This is a global option and it will be valid for all the controller's raidgroups whether they are containing SSDs or not.

IMHO, it is certainly not a best practice.

Saying raid-DP would recover faster than raid-4 with spare, because the "spare" would already be hot, is an absolute nonsense.

Since the SSD is in the aggregate, it's not a spare disk, it's a parity disk. If one SSD fails, aggregate will be in a degraded condition with no spare to rebuild and you will not be warned of the low spare condition since you disabled it.

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Re: OK to convert a Flash Pool from RAID-DP to RAID4?

Can you elaborate, our Netapp SE is still insisting that raid-dp would be best.  I get that we will not be warned about the low spare condition(which we hope to get past with proper monitoring, and as I understand it, the autosupport request for disk replacement would still work), but otherwise,  the failure condition seems the same(two disks can fail before we have data loss), and the recovery time seems like it would be faster on raid-dp. I don't see how it's "absolute nonsense"

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Re: OK to convert a Flash Pool from RAID-DP to RAID4?

For Cluster Mode with 8.2 and higher:

 

Change Raid Group type for SSD disks on Hybrid aggr:

cl1:: > aggr modify -aggregate aggr_d01 -raidtype raid4 -disktype SSD

 

Then add the relised disk to the aggr:

cl1:: > aggr add-disks -aggregate aggr_d01 -disktype SSD -raidgroup rg1 -diskcount 1

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Re: OK to convert a Flash Pool from RAID-DP to RAID4?

Thanks TREBOR2000! Your solution worked like a charm!

 

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