Re: nvd->nda switch and blocksize changes for ZFS
Date: Mon, 25 Sep 2023 06:42:08 UTC
Hi Dimitry, Yuri and also Mark, thanks for your fast responses! Am 23.09.2023 um 20:58 schrieb Yuri Pankov: > Dimitry Andric wrote: >> On 23 Sep 2023, at 18:31, Frank Behrens<frank@harz2023.behrens.de> wrote: >>> I created a zpool with a FreeBSD-14.0-CURRENT on February. With >>> 15.0-CURRENT/14.0-STABLE from now I get the message: >>> >>> status: One or more devices are configured to use a non-native block >>> size. >>> Expect reduced performance. >>> action: Replace affected devices with devices that support the >>> configured block size, or migrate data to a properly configured >>> pool. >>> NAME STATE READ WRITE CKSUM >>> zsys ONLINE 0 0 0 >>> raidz1-0 ONLINE 0 0 0 >>> nda0p4 ONLINE 0 0 0 block size: 4096B configured, 16384B native >>> nda1p4 ONLINE 0 0 0 block size: 4096B configured, 16384B native >>> nda2p4 ONLINE 0 0 0 block size: 4096B configured, 16384B native >>> >>> I use: >>> nda0: <Samsung SSD 980 1TB ..> >>> nda0: nvme version 1.4 >>> nda0: 953869MB (1953525168 512 byte sectors) >>> >>> I cannot imagine, that the native blocksize changed. Do I really >>> expect a reduced performance? >>> Is it advisable to switch back to nvd? >> It could be due to a bug in nda so it reports the native block size >> incorrectly, in which case you would not need to do anything but >> ignore the message. However, if the native block size is really >> 16kiB, you will get write amplification effects, which could >> needlessly shorten the life of your SSD. >> >> I would try running e.g. smartmontools's smartctl, which can >> sometimes tell you what the real block size is. Although as far as I >> know, it retrieves this information from some internal database. You >> could also try to look up the information in the SSD vendor's data >> sheet, or ask the vendor directly? > Isn't it displayed by e.g. `nvmecontrol identify nda0` under the LBA > Formats (including the current one used to format the namespace)? Based on your comments I made some investigations and switched back to nvd: # smartctl -a /dev/nvme0 Namespace 1 Formatted LBA Size: 512 ... Supported LBA Sizes (NSID 0x1) Id Fmt Data Metadt Rel_Perf 0 + 512 0 0 # nvmecontrol identify nda0 and # nvmecontrol identify nvd0 (after hw.nvme.use_nvd="1" and reboot) give the same result: Number of LBA Formats: 1 Current LBA Format: LBA Format #00 LBA Format #00: Data Size: 512 Metadata Size: 0 Performance: Best ... Optimal I/O Boundary: 0 blocks NVM Capacity: 1000204886016 bytes Preferred Write Granularity: 32 blocks Preferred Write Alignment: 8 blocks Preferred Deallocate Granul: 9600 blocks Preferred Deallocate Align: 9600 blocks Optimal Write Size: 256 blocks The recommended blocksize for ZFS is GEOM's stripesize and there I see a difference: # diff -w -U 10 gpart_list_nvd.txt gpart_list_nda.txt -Geom name: nvd0 +Geom name: nda0 modified: false state: OK fwheads: 255 fwsectors: 63 last: 1953525127 first: 40 entries: 128 scheme: GPT Providers: -1. Name: nvd0p1 +1. Name: nda0p1 Mediasize: 272629760 (260M) Sectorsize: 512 - Stripesize: 4096 - Stripeoffset: 0 + Stripesize: 16384 + Stripeoffset: 4096 Mode: r1w1e2 efimedia: HD(1,GPT,8d4c57bb-932f-11ed-82da-74563c227532,0x28,0x82000) rawuuid: 8d4c57bb-932f-11ed-82da-74563c227532 rawtype: c12a7328-f81f-11d2-ba4b-00a0c93ec93b label: efiboot0 length: 272629760 offset: 20480 type: efi index: 1 end: 532519 start: 40 ... -4. Name: nvd0p4 +4. Name: nda0p4 Mediasize: 995635494912 (927G) Sectorsize: 512 - Stripesize: 4096 + Stripesize: 16384 Stripeoffset: 0 Mode: r1w1e1 efimedia: HD(4,GPT,8d61a5ca-932f-11ed-82da-74563c227532,0x882800,0x73e84000) rawuuid: 8d61a5ca-932f-11ed-82da-74563c227532 rawtype: 516e7cba-6ecf-11d6-8ff8-00022d09712b label: zfs0 length: 995635494912 offset: 4568645632 type: freebsd-zfs index: 4 end: 1953523711 start: 8923136 With these information I'm not sure, if I have really a problem with the native blocksize. Does anybody know, how the stripesize is determined? Kind regards, Frank -- Frank Behrens Osterwieck, Germany