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| name | type | description | model | distro | kernel | SATA | USB | Purchased |
|---|---|---|---|---|---|---|---|---|
| rc66 | server | This is the machine type I'd like to use (we have 80 of them). | Supermicro xx | RHEL6 | 2.6.32 | 3gbps | 2.0 | 2011 |
| rcmonster | server | This is a newer, beefier machine with Intel 520 drives, but also stuck on RHEL6. | Intel xx | RHEL6 | 2.6.32 | 6gbps | 3.0 | 2013 |
| flygecko | desktop | This is a newer desktop machine with a newer version of Linux. | Supermicro xx? | Arch | 3.12 | 3gbps | 2.0 | 2013 |
| x1 | laptop | This is a laptop with a newer version of Linux. | Lenovo Thinkpad X1 Carbon | Debian Jessie | 3.12 | mSATA 6gbps | 3.0 | 2012 |
Disks
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These are the disks I've tried:
| model | qty | performance | |
|---|---|---|---|
| Crucial M4 | 160 | ||
| Intel 520 (SSDSC2CW120A3) | 2 | Intel ?? on flygecko<1ms per write on rc66, rcmonster | |
| Intel X25-M (SSDSA2M120G2GC) | 1 | <1ms per write on flygecko | |
| Intel 530 (SSDSC2BW120A4) | 5 | 10ms per write on rc66, rcmonster, and flygecko | |
| Intel 530 attached over USB-to-SATA adapter | 1 | <1ms per write on rc66, rcmonster, flygecko, and x1 | |
| Cheap USB thumb drive | 1n |
Negative Results
- The first thing I did was update from the DC22 firmware to the current DC33 firmware. No effect.
- I tried a machine with 6gbps SATA (rcmonster). No effect.
- I tried a machine with a newer kernel (flygecko). No effect.
- I tried disabling APM power saving with hdparm -B. No effect.
- Did I try different NCQ sizes? Doesn't work on some machines.
- I tried changing the I/O scheduler. This shouldn't have an effect since there's only one I/O outstanding at a time. No effect.
- I tried running the benchmark on the raw block device rather than an ext4 partition. This helped but only slightly, reducing latency per write from 10ms to about 9ms.
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