[gpfsug-discuss] Metadata with GNR code

[Simon Thompson]

Just wondering if anyone has any strong views/recommendations with metadata when using GNR code?

I know in “san” based GPFS, there is a recommendation to have data and metadata split with the metadata on SSD.

I’ve also heard that with GNR there isn’t much difference in splitting data and metadata.

We’re looking at two systems and want to replicate metadata, but not data (mostly) between them, so I’m not really sure how we’d do this without having separate system pool (and then NSDs in different failure groups)….

If we used 8+2P vdisks for metadata only, would we still see no difference in performance compared to mixed (I guess the 8+2P is still spread over a DA so we’d get half the drives in the GNR system active…).

Or should we stick SSD based storage in as well for the metadata pool? (Which brings an interesting question about RAID code related to the recent discussions on mirroring vs RAID5…)

Thoughts welcome!

Simon
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