[gpfsug-discuss] gpfs performance monitoring
Salvatore Di Nardo
sdinardo at ebi.ac.uk
Thu Sep 4 14:25:09 BST 2014
> >> Yes, we have dedicate vdisks for metadata, but they are in the same
> declustered arrays/recoverygroups, so they whare the same spindles
> Thats imho not a good approach. Metadata operation are small and
> random, data io is large and streaming.
> Just think you have a highway full of large trucks and you try to get
> with a high speed bike to your destination. You will be blocked.
> The same problem you have at your destiation. If many large trucks
> would like to get their stuff off there is no time for somebody with a
> small parcel.
> Thats the same reason why you should not access tape storage and disk
> storage via the same FC adapter. ( Streaming IO version v.
> random/small IO )
> So even without your current problem and motivation for measureing i
> would strongly suggest to have at least dediacted SSD for metadata and
> if possible even dedicated NSD server for the metadata.
> Meaning have a dedicated path for your data and a dedicated path for
> your metadata.
> All from a users point of view
That's where i was puzzled too. GSS its a gpfs appliance and came
configured this way. Also official GSS documentation suggest to create
separate vdisks for data and meatadata, but in the same declustered
arrays. I always felt this a strange choice, specially if we consider
that metadata require a very small abbount of space, so few ssd could do
More information about the gpfsug-discuss