Re: mkfs.btrfs doesn't detect SSD
On 2015-11-07 10:30, Christoph Anton Mitterer wrote: Hmm in fact it seems to be the kernel who wrongly, detects the type: /sys/block/sdb/queue/rotational = 1 or more like the USB/SATA bridge simply reports it wrong. Anyway, is there a way to override? Or will setting /sys/block/sdb/queue/rotational = 0 give the expected behaviour? This is a common issue with many USB/SATA bridges (and also device-mapper and MD devices), which don't properly query the attached device and modify the properties they report to the host system. If you have some way to reliably identify this particular device, you could add a udev rule to automatically set it as non-rotational. You could also do like you suggested and set it to non-rotational manually, although for mkfs at least, it's quicker to just manually specify '-m single' on the command-line (that's the only difference in mkfs behavior for a SSD). Like Chris said in his reply though, everything other than using single profile for metadata is done at mount time (if queue/rotational is 0, then -o ssd does get added to the mount options automatically, but it's a lot clearer to just specify the option yourself). smime.p7s Description: S/MIME Cryptographic Signature
mkfs.btrfs doesn't detect SSD
Hey. I'm creating a filesystem on Samsung Evo 850 Pro on top of a dm- crypt/LUKS container (with TRIM not being passed on, for the usual security reasons): # mkfs.btrfs --label system /dev/mapper/system btrfs-progs v4.2.2 See http://btrfs.wiki.kernel.org for more information. Label: system UUID: 65531196-2e43-4c49-b495-ac9abc57d7d8 Node size: 16384 Sector size:4096 Filesystem size:937.00GiB Block group profiles: Data: single8.00MiB Metadata: DUP 1.01GiB System: DUP 12.00MiB SSD detected: no Incompat features: extref, skinny-metadata Number of devices: 1 Devices: IDSIZE PATH 1 937.00GiB /dev/mapper/system As you can see it doesn't detect the SSD. Isn't that kinda problematic cause btrfs does more when it detects and SSD than just using TRIM (e.g. not DUPing meta-data)? Can I somehow override this to get the SSD "detected"? Or what is the general suggestion here? Having it handled as SSD or as non-SSD, as said, when dm-crypt is used below and TRIM is not intended to be used. Cheers, Chris. smime.p7s Description: S/MIME cryptographic signature
Re: mkfs.btrfs doesn't detect SSD
On Sat, Nov 7, 2015 at 4:05 PM, Christoph Anton Mittererwrote: > Hey. > > I'm creating a filesystem on Samsung Evo 850 Pro on top of a dm- > crypt/LUKS container (with TRIM not being passed on, for the usual > security reasons): > # mkfs.btrfs --label system /dev/mapper/system > btrfs-progs v4.2.2 > See http://btrfs.wiki.kernel.org for more information. > > Label: system > UUID: 65531196-2e43-4c49-b495-ac9abc57d7d8 > Node size: 16384 > Sector size:4096 > Filesystem size:937.00GiB > Block group profiles: > Data: single8.00MiB > Metadata: DUP 1.01GiB > System: DUP 12.00MiB > SSD detected: no > Incompat features: extref, skinny-metadata > Number of devices: 1 > Devices: >IDSIZE PATH > 1 937.00GiB /dev/mapper/system > > > As you can see it doesn't detect the SSD. > Isn't that kinda problematic cause btrfs does more when it detects and > SSD than just using TRIM (e.g. not DUPing meta-data)? > > Can I somehow override this to get the SSD "detected"? > Or what is the general suggestion here? Having it handled as SSD or as > non-SSD, as said, when dm-crypt is used below and TRIM is not intended > to be used. There are three separate SSD related optimizations: Allocation optimization is the mount time -o ssd and ssd_spread options; which on dmcrypt devices you'll need to manually add because the fact this is an SSD isn't passed through the device mapper apparently. Using single instead of duplicate metadata is a mkfs time option, probably uses the same detection method as mount time allocation optimization, and why you get DUP instead of single. So you have to mkfs manually or use 'btrfs balance -mconvert=single -f' to force changing it, forcing is required since a reduction in redunancy will happen. Trim, isn't used automatically, it's a mount time option, -o discard. -- Chris Murphy -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: mkfs.btrfs doesn't detect SSD
Hmm in fact it seems to be the kernel who wrongly, detects the type: /sys/block/sdb/queue/rotational = 1 or more like the USB/SATA bridge simply reports it wrong. Anyway, is there a way to override? Or will setting /sys/block/sdb/queue/rotational = 0 give the expected behaviour? Thanks, Chris. smime.p7s Description: S/MIME cryptographic signature