Messages in this thread | | | Date | Tue, 26 Feb 2013 20:41:36 +0200 | From | Marcus Sundman <> | Subject | Re: Debugging system freezes on filesystem writes |
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On 24.02.2013 03:20, Theodore Ts'o wrote: > On Sun, Feb 24, 2013 at 11:12:22AM +1100, Dave Chinner wrote: >>>> /dev/sda6 /home ext4 rw,noatime,discard 0 0 >> ^^^^^^^ >> I'd say that's your problem.... > Looks like the Sandisk U100 is a good SSD for me to put on my personal > "avoid" list: > > http://thessdreview.com/our-reviews/asus-zenbook-ssd-review-not-necessarily-sandforce-driven-shows-significant-speed-bump/ > > There are a number of SSD's which do not implement "trim" efficiently, > so these days, the recommended way to use trim is to run the "fstrim" > command out of crontab.
OK. Removing 'discard' made it much better (the 60-600 second freezes are now 1-50 second freezes), but it's still at least an order of magnitude worse than a normal HD. When writing, that is -- reading is very fast (when there's no writing going on).
So, after reading up a bit on this trimming I'm thinking maybe my filesystem's block sizes don't match up with my SSD's blocks (or whatever its write unit is called). Then writing a FS block would always write to multiple SSD blocks, causing multiple read-erase-write sequences, right? So how can I check this, and how can I make the FS blocks match the SSD blocks?
Best regards, Marcus
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