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Am 20.06.2013 21:10, schrieb Mark Knecht: |
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> Hi, |
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> Does anyone know of info on how the starting sector number might |
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> impact RAID performance under Gentoo? The drives are WD-500G RE3 |
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> drives shown here: |
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> |
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> http://www.amazon.com/Western-Digital-WD5002ABYS-3-5-inch-Enterprise/dp/B001EMZPD0/ref=cm_cr_pr_product_top |
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> |
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> These are NOT 4k sector sized drives. |
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> |
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> Specifically I'm a 5-drive RAID6 for about 1.45TB of storage. My |
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> benchmarking seems abysmal at around 40MB/S using dd copying large |
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> files. It's higher, around 80MB/S if the file being transferred is |
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> coming from an SSD, but even 80MB/S seems slow to me. I see a LOT of |
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> wait time in top. And my 'large file' copies might not be large enough |
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> as the machine has 24GB of DRAM and I've only been copying 21GB so |
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> it's possible some of that is cached. |
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> |
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> Then I looked again at how I partitioned the drives originally and |
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> see the starting sector of sector 3 as 8594775. I started wondering if |
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> something like 4K block sizes at the file system level might be |
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> getting munged across 16k chunk sizes in the RAID. Maybe the blocks |
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> are being torn apart in bad ways for performance? That led me down a |
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> bunch of rabbit holes and I haven't found any light yet. |
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> |
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> Looking for some thoughtful ideas from those more experienced in this area. |
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> |
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> Cheers, |
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> Mark |
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> |
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> |
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|
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man mkfs.xfs |
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|
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man mkfs.ext4 |
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|
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look for stripe size etc. |
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|
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Have fun. |
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