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dell 2T 7.2k nearline SAS 6Gbps- ingress/egress throughput

I don't have access to machine/drive, but need to define specs to purchase one.

What all things would it be dependent on? Using RAID 10, would improve it?

Would it be dependent on file size, which we read or write?

How to calculate latency of fetching a file segment? Seek time etc..

I need to use it with a web server, for storing and delivering large no. of small files. There will be continuous writes and reads 24x7 of small files. Any recommendations for which RAID to use, or no RAID should be used, based on writes or reads?

Say if I choose, dell 2T 7.2k nearline SAS 6Gbps- how to calculate ingress/egress throughput?

Edit (More info):

  • Raid Controller - PERC H700 Integrated RAID Controller, 512MB Cache, For x6 Backplane
  • 6 x 2TB Near Line SAS 6Gbps 7.2k 3.5" HD Hot Plug. I need atleast 8TB storage. Planning to use RAID 10.
  • Typical file size range: 100KB - 1MB
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Nagota
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  • I'm not going to answer, but you should bear this in mind. 7200 disks are slooow - if you can afford it, get 10k or 15k. You should also bear in mind larger capacity disks will take longer to rebuild in the event of a disk failure, thus increasing your risk of double disk failure. – Ben Pilbrow Oct 01 '11 at 10:15
  • @BenPilbrow Yeah, but 10k, 15k disks are too expensive. And I need atleast about 8TB of storage, on server. – Nagota Oct 01 '11 at 10:38

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Using RAID will improve it, but only if you choose an appropriate stripe size, if you have several small files, a smaller stripe size is recommended. And I think the only way to calculate is to put it to the test, every case is different.

How many drives will you use? What raid controller will you use?

Ben Pilbrow
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Lucas Kauffman
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  • Radi Controller - PERC H700 Integrated RAID Controller, 512MB Cache, For x6 Backplane 6 x 2TB Near Line SAS 6Gbps 7.2k 3.5" HD Hot Plug. I need lots of storage. Typical file size range: 100KB - 1MB – Nagota Oct 01 '11 at 10:33