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On 04/26 03:29, Rich Freeman wrote: |
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> On Sun, Apr 26, 2020 at 12:15 PM <tuxic@××××××.de> wrote: |
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> > |
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> > On 04/26 11:20, Rich Freeman wrote: |
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> > > On Sun, Apr 26, 2020 at 10:52 AM <tuxic@××××××.de> wrote: |
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> > > > |
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> > > > Fstrim reports about 200 GiB of trimmed data. |
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> > > > |
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> > > |
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> > > My suggestion would be to run fstrim twice in a row and see how fast |
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> > > it operates and what the results are. If the second one completes |
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> > > very quickly that suggests that the drive is sane. I'd probably just |
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> > > run it daily in that case, but weekly is probably fine especially if |
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> > > the drive isn't very full. |
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> > > |
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> > |
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> > host:/root>fstrim -v / |
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> > /: 3.3 GiB (3578650624 bytes) trimmed |
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> > host:/root>fstrim -v / |
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> > /: 0 B (0 bytes) trimmed |
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> > |
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> > This time the first fstrim reports a small mount of trimmed |
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> > data and second one no fstrimmed data at all. |
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> > |
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> |
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> Ok, I became a bit less lazy and started looking at the source. |
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> |
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> All fstrim does is send an FITRIM ioctl to the kernel for the device. |
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> This is implemented in a filesystem-dependent manner, and I couldn't |
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> actually find any documentation on it (actual documentation on the |
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> ioctl - not the fstrim manpage/etc). A quick glimpse at the ext4 |
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> source suggests that ext4 has a flag that can track whether a group of |
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> blocks has been trimmed yet or not since it was last deallocated. So |
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> ext4 will make repeated fstrim runs a no-op and the drive won't see |
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> these. |
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> |
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> At least, that was what I got after about 5-10min of browsing. I |
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> didn't take the time to grok how ext4 tracks free space and so on. |
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> |
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> Incidentally, in the other thread the reason that dry-run didn't |
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> report anything to be trimmed is that this is hard-coded: |
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> printf(_("%s: 0 B (dry run) trimmed on %s\n"), path, devname); |
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> https://github.com/karelzak/util-linux/blob/master/sys-utils/fstrim.c#L109 |
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> |
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> Otherwise the ioctl returns how much space was trimmed, and fstrim outputs this. |
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> |
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> -- |
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> Rich |
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> |
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|
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Hi Rich, |
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|
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thank you very much for digging into the depth of the sources and for |
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explaining it!!! Very appreciated !!! :) :) |
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|
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To implement a dry run with a printf() is new to me... ;) |
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|
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Cheers! |
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Meino |
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