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Journal luns from flash drives
We have unity all flash :
Is it recommended to create production lun and journal lun from same pool or we have to segregate it .Array is unity all flash
Is it recommended to create a journal lun as thin lun as the disks are all flash
forshr
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August 14th, 2017 02:00
If you have sufficient number of drives to facilitate separation (post sizing for the journal requirement) then this would be the best practice.
Regarding the use of a journal LUN as thin, this is impractical because the journal will fill to its limit and then data is constantly written on a new for old basis. So the journal will inflate and stay permanently inflated.
Regards,
Rich
ksun87
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August 28th, 2017 20:00
is there a technical reason to separate pools for journals on an AFA? In the past it made sense since we were carving journals out of high performance disks in a RAID group but does this change for an all flash array? I can see we would be utilizing a specific set of flash drives out of that pool for journaling but would it be OK to use one pool?
Also, do we still want to do multiple smaller journals on all flash? IE: 3 x 50 GB journals for 150 GB journal volume?
forshr
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August 29th, 2017 02:00
The technical reason is related to performance which would be the potential for concurrent writes and reads to the same drive which could be further exacerbate with local copy replication existing on the same array as the array with the remote replica copy.