On 11/3/2017 1:31 AM, hw wrote:
2.5" SAS drives spinning at 10k and 15k RPM are the performance
solution for online storage, like databases and so forth. also make
more sense for large arrays of SSDs, as they don't even come in
3.5". With 2.5" you can pack more disks per U (24-25 2.5" per 2U
face, vs 12 3.5" max per 2U)... more disks == more IOPS.
That´s not for storage because it´s so expensive that you can only use it
for the limited amounts of data that actually benefit from, or require,
the advantage in performance. For this application, it makes perfectly
sense.
online high performance storage, vs nearline/archival storage. the first
needs high IOPS and high concurrency. the 2nd needs high capacity,
fast sequential speeds but little or no random access.. two
completely different requirements. both are 'storage'.
3.5" SATA drives spinning at 5400 and 7200 rpm are the choice for
large capacity bulk 'nearline' storage which is typically
sequentially written once
Why would you write them only once? Where are you storing your data
when you
do that?
I meant to say write occasionally. on a nearline bulk system, files
tend to get written sequentially, and stored for a long time.
--
john r pierce, recycling bits in santa cruz
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