Date: Tue, 29 May 2012 22:59:58 +0200 From: Kees Jan Koster <kjkoster@gmail.com> To: Gary Palmer <gpalmer@freebsd.org> Cc: freebsd-stable@freebsd.org Subject: Re: FreeBSD 9.0 hangs on heavy I/O Message-ID: <43F6FDD2-3D31-44D7-82C7-4466D609ECF2@gmail.com> In-Reply-To: <20120529203913.GB92444@in-addr.com> References: <BD5D6BB6-8CFF-456A-B03E-05454EB03AB6@gmail.com> <20120529203913.GB92444@in-addr.com>
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Dear Gary,
>> # camcontrol devlist
>> <WDC WD740ADFD-00NLR1 20.07P20> at scbus1 target 0 lun 0 (pass0,ada0)
>> <WDC WD740GD-00FLC0 33.08F33> at scbus2 target 0 lun 0 (pass1,ada1)
>> <WDC WD740GD-00FLC0 33.08F33> at scbus3 target 0 lun 0 (pass2,ada2)
>> <OCZ SUMMIT VBM1801Q> at scbus4 target 0 lun 0 (pass3,ada3)
>> <PepperC Virtual Disc 1 0.01> at scbus7 target 0 lun 0 (pass4,cd0)
>> <PepperC Virtual Disc 2 0.01> at scbus8 target 0 lun 0 (pass5,cd1)
>
> Check the SSD for its internal block size and make sure your filesystem
> and partitions are aligned with the disk block size. Unless there
> is something wrong with your SATA controller I'd expect a lot more than
> 273 IOPS/sec and ~30MByte/sec from a SSD.
Thank you for suggesting this. However, I recently went through my file systems to fix disk alignment. I ended up aligning them to 1M blocks, which raised the throughput from 6M/s to about 60-80MB/s which is what I am seeing today.
# gpart show
...
=> 34 250069613 ada3 GPT (119G)
34 2014 - free - (1M)
2048 250067599 1 freebsd-ufs (119G)
Do you think I need to revisit alignment?
--
Kees Jan
http://java-monitor.com/
kjkoster@kjkoster.org
+31651838192
Change is good. Granted, it is good in retrospect, but change is good.
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