On 07/09/12 13:23, Steven Chamberlain wrote: [...] > Plain UFS could be expected to be slow. Because it is unjournalled, I > think metadata updates are forced to be synchronous. On my amd64 box, plain UFS goes like greased lightning --- I was very impressed. That's a much more modern hard drive, though (a spinning once). [...] > The `camcontrol identify ada0` command should show the status of a > disk's write cache (and sysctl hw.ata.wc must also be 1). I think it > will be 'on', but the sync updates of metadata might mean it is flushed > regularly. Apparently the eee SSD is pants: device model SILICONMOTION SM223AC [...] Feature Support Enabled Value Vendor read ahead no no write cache no no flush cache no no overlap no Tagged Command Queuing (TCQ) no no Native Command Queuing (NCQ) no SMART yes yes microcode download no no security no no power management yes no advanced power management yes no 0/0x00 automatic acoustic management no no media status notification no no power-up in Standby no no write-read-verify no no unload no no free-fall no no data set management (TRIM) no It's a native SATA SSD with no TRIM! *cringe* Turning softupdates on made the problem go away entirely; thanks. I had previously wondered about this, but my last experience with softupdates was on OpenBSD and that enables it via a mount option --- I didn't think to look at tunefs... $ time mkdir {0,1,2,3,4,5,6,7,8,9}{0,1,2,3,4,5,6,7,8,9}{0,1,2,3,4,5,6,7,8,9} real 0m2.321s $ time rmdir {0,1,2,3,4,5,6,7,8,9}{0,1,2,3,4,5,6,7,8,9}{0,1,2,3,4,5,6,7,8,9} real 0m0.467s Actually turning it on was an exercise in frustration, as you don't seem to be able to use tunefs on a mounted file system and of course this was my root partition... eventually I had to use a FreeBSD live USB image and boot from that. Given what a vast difference it makes (more or less the difference between a usable system and an unusable one, on the eee) I would certainly suggest enabling it by default. Is there any reason *not* to want softupdates? I notice that my partitions do seem to be unaligned, but I don't recall now whether I let the installer repartition my disk or not. As I don't have TRIM anyway it's probably not important now. [...] > ZFS should of course be unaffected by the above issue, and be the > best-performing choice of filesystem here. Is ZFS viable on a 32-bit system? The FreeBSD wiki page on it (which, being a wiki, is of course out of date, unrepresentative and probably wrong) claims that these system is still prone to running out of memory and panicking. -- ┌─── dg@cowlark.com ───── http://www.cowlark.com ───── │ │ life←{ ↑1 ⍵∨.^3 4=+/,¯1 0 1∘.⊖¯1 0 1∘.⌽⊂⍵ } │ --- Conway's Game Of Life, in one line of APL
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