On Tue, Mar 24, 2020 at 9:01 PM Chao Yu <yuch...@huawei.com> wrote: > I guess ssd should support discard, however I saw sdb was wrapped with device > mapper, which may have different character, just want to check that whether > device mapper disable the discard. > > If backup/restore is hard for you, how about let me add some logs on fstrim > interface? then we could retry fstrim to see where we actually fail.
I have an older totally different SSD for testing that seems to support discard: # hdparm -I /dev/sdc | grep TRIM * Data Set Management TRIM supported (limit 8 blocks) * Deterministic read ZEROs after TRIM As I test, I created two f2fs partitions on this different SSD: 1) /dev/sdc2 normal F2FS 2) /dev/sdc3 encrypted with LUKS (dm-crypt) then formatted to F2FS Results: 1) Regular F2FS # fstrim -v /regular /regular: 0 B (0 bytes) trimmed 2) Encrypted F2FS # fstrim -v /encrypted fstrim: /encrypted: the discard operation is not supported Can we conclude that the device mapper is some how spoofing fstrim into thinking the device doesn't support trim? Happy to hear your thoughts. _______________________________________________ Linux-f2fs-devel mailing list Linuxfirstname.lastname@example.org https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel