That sounds about right. 69T x 0.76 = 52.44T Laura: Thanks for the info about SPA slop space.
Raj: Thanks for that URL. It looks very handy. --Rick On 4/6/21, 5:19 PM, "lustre-discuss on behalf of Saravanaraj Ayyampalayam via lustre-discuss" <[email protected] on behalf of [email protected]> wrote: I think you are correct. ‘zpool list’ shows raw space, ‘zfs list’ shows the space after reservation for parity, etc.. In a 10 disk raidz2 ~24% of the space is reserved for parity.This website helps in calculating ZFS capacity. https://wintelguy.com/zfs-calc.pl -Raj On Apr 6, 2021, at 4:56 PM, Laura Hild via lustre-discuss <[email protected]> wrote: > I am not sure about the discrepancy of 3T. Maybe that is due to some ZFS and/or Lustre overhead? Slop space? https://openzfs.github.io/openzfs-docs/Performance%20and%20Tuning/Module%20Parameters.html#spa-slop-shift -Laura ________________________________________ Od: lustre-discuss <[email protected]> v imenu Mohr, Rick via lustre-discuss <[email protected]> Poslano: torek, 06. april 2021 16:34 Za: Makia Minich <[email protected]>; [email protected] <[email protected]> Zadeva: Re: [lustre-discuss] [EXTERNAL] ZFS and OST Space Difference Makia, The drive sizes are 7.6 TB which translates to about 6.9 TiB (which is the unit that zpool uses for "T"). So the zpool sizes as just 10 x 6.9T = 69T since zpool shows the total amount of disk space available to the pool. The usable space (which is what df is reporting) should be more like 0.8 x 69T = 55T. I am not sure about the discrepancy of 3T. Maybe that is due to some ZFS and/or Lustre overhead? --Rick On 4/6/21, 3:49 PM, "lustre-discuss on behalf of Makia Minich" <[email protected] on behalf of [email protected]> wrote: I believe this was discussed a while ago, but I was unable to find clear answers, so I’ll re-ask in hopefully a slightly different way. On an OST, I have 30 drives, each at 7.6TB. I create 3 raidz2 zpools of 10 devices (ashift=12): [root@lustre47b ~]# zpool list NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT oss55-0 69.9T 37.3M 69.9T - - 0% 0% 1.00x ONLINE - oss55-1 69.9T 37.3M 69.9T - - 0% 0% 1.00x ONLINE - oss55-2 69.9T 37.4M 69.9T - - 0% 0% 1.00x ONLINE - [root@lustre47b ~]# Running a mkfs.lustre against these (and the lustre mount) and I see: [root@lustre47b ~]# df -h | grep ost oss55-0/ost165 52T 27M 52T 1% /lustre/ost165 oss55-1/ost166 52T 27M 52T 1% /lustre/ost166 oss55-2/ost167 52T 27M 52T 1% /lustre/ost167 [root@lustre47b ~]# Basically, we’re seeing a pretty dramatic loss in capacity (156TB vs 209.7TB, so a loss of about 50TB). Is there any insight on where this capacity is disappearing to? If there some mkfs.lustre or zpool option I missed in creating this? Is something just reporting slightly off and that space really is there? Thanks. — Makia Minich Chief Architect System Fabric Works "Fabric Computing that Works” "Oh, I don't know. I think everything is just as it should be, y'know?” - Frank Fairfield _______________________________________________ lustre-discuss mailing list [email protected] https://urldefense.proofpoint.com/v2/url?u=http-3A__lists.lustre.org_listinfo.cgi_lustre-2Ddiscuss-2Dlustre.org&d=DwIGaQ&c=CJqEzB1piLOyyvZjb8YUQw&r=897kjkV-MEeU1IVizIfc5Q&m=habzcIRCKUXYLTbJVvgv2fPgmEuBnVtUdsgTfIsAHZY&s=M7RWFzL5Xm7uDovhMY_cI9Hvk-jWavZyfLWjpMSAs1E&e= _______________________________________________ lustre-discuss mailing list [email protected] http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org _______________________________________________ lustre-discuss mailing list [email protected] http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org
