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Re: Diagnosing a performance bottleneck in BACKUP/LIST

 
Bob Blunt
Respected Contributor

Re: Diagnosing a performance bottleneck in BACKUP/LIST

AND, possibly, get a copy of the SWXCR utilities loaded on the system so you can get a better idea about the drives using swxcrmgr online. Writing to a RAID unit with a failed drive will certainly be much slower. Definitely capture a BACKUP before any work gets done on that RAIDset but I know you knew that already.

Then I'd compress the data on that drive since their free space is pretty well sliced and diced (or, maybe, find another more dedicated space like making a LD partition or RAM disk just for the listing for top speed.

I may have a copy of the SWXCR utils...

bob
GuentherF
Trusted Contributor

Re: Diagnosing a performance bottleneck in BACKUP/LIST

Write to RAID-5 in redundant state:

- read old data (maybe from cache)
- read old parity (maybe from cache)
- write new parity
- write new data

RAID-5 array reduced:

if parity disk for this write is missing
- write data
else if data disk for this write is missing
- read old parity (maybe from cache)
- write new parity
else
- read old data (maybe from cache)
- read old parity (maybe from cache)
- write new parity
- write new data

So writing to a reduced array is never slower than writing to a redundant array.

/Guenther