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Yo Duncan! |
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On Fri, 28 Jun 2013 09:12:24 +0000 (UTC) |
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Duncan <1i5t5.duncan@×××.net> wrote: |
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> Duncan posted on Fri, 28 Jun 2013 03:36:10 +0000 as excerpted: |
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> |
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> I settled on a 4 GiB file. Speeds are power-of-10-based since that's |
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> what dd reports, unless otherwise stated. |
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dd is pretty good at testing linear file performance, pretty useless |
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for testing mysql performance. |
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> To SSD: peak was upper 250s MB/s over a wide blocksize range of 1 MiB |
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> >From SSD: peak was lower 480s MB/s, blocksize 32 KiB to 512 KiB |
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Sounds about right. Your speeds are now so high that small differences |
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in the SATA controller chip will be bigger than that between some |
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SSD drives. Use a PCIe/SATA card and your performance will drop from |
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what you see. |
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> Spinning rust speeds, single Seagate st9500424as, 7200rpm 2.5" 16MB |
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Those are pretty old and slow. If you are going to test an HDD against a |
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newer SSD you should at least test a newer HDD. A new 2TB drive could |
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get pretty close to your SSD performance in linear tests. |
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> To rust: upper 70s MB/s, blocksize didn't seem to matter much. |
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> >From rust: upper 90s MB/s, blocksize upto 4 MiB. |
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Seems about right, for that drive. |
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I think your numbers are about right, if your workload is just reading |
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and writing big linear files. For a MySQL workload there would be a lot |
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of random reads/writes/seeks and the SSD would really shine. |
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RGDS |
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GARY |
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--------------------------------------------------------------------------- |
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97701 |
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gem@××××××.com Tel:+1(541)382-8588 |
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