<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Thanks to Rick, Raj, and Laura for helping to understand all of this a bit more.<br class=""><div class=""><br class="webkit-block-placeholder"></div><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class=""><div class="">\u2014<br class=""></div><div class=""><br class=""></div><div class="">Makia Minich<br class=""></div><div class="">Chief Architect<br class=""></div><div class="">System Fabric Works<br class="">"Fabric Computing that Works\u201d<br class=""><br class="">"Oh, I don't know. I think everything is just as it should be, y'know?\ufeff\u201d<br class="">- Frank Fairfield</div></div></div></div></div>
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<div><br class=""><blockquote type="cite" class=""><div class="">On Apr 6, 2021, at 5:48 PM, Mohr, Rick via lustre-discuss <<a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div class="">That sounds about right. 69T x 0.76 = 52.44T<br class=""><br class="">Laura: Thanks for the info about SPA slop space.<br class=""><br class="">Raj: Thanks for that URL. It looks very handy.<br class=""><br class="">--Rick<br class=""><br class="">\ufeffOn 4/6/21, 5:19 PM, "lustre-discuss on behalf of Saravanaraj Ayyampalayam via lustre-discuss" <<a href="mailto:lustre-discuss-bounces@lists.lustre.org" class="">lustre-discuss-bounces@lists.lustre.org</a> on behalf of <a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a>> wrote:<br class=""><br class=""> I think you are correct. \u2018zpool list\u2019 shows raw space, \u2018zfs list\u2019 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. <a href="https://wintelguy.com/zfs-calc.pl" class="">https://wintelguy.com/zfs-calc.pl</a><br class=""><br class=""> -Raj<br class=""><br class=""><br class=""> On Apr 6, 2021, at 4:56 PM, Laura Hild via lustre-discuss <<a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a>> wrote:<br class=""><br class=""><blockquote type="cite" class="">I am not sure about the discrepancy of 3T. Maybe that is due to some ZFS and/or Lustre overhead?<br class=""></blockquote><br class=""> Slop space?<br class=""><br class=""> <a href="https://openzfs.github.io/openzfs-docs/Performance%20and%20Tuning/Module%20Parameters.html#spa-slop-shift" class="">https://openzfs.github.io/openzfs-docs/Performance%20and%20Tuning/Module%20Parameters.html#spa-slop-shift</a><br class=""><br class=""> -Laura<br class=""><br class=""><br class=""><br class=""> ________________________________________<br class=""> Od: lustre-discuss <<a href="mailto:lustre-discuss-bounces@lists.lustre.org" class="">lustre-discuss-bounces@lists.lustre.org</a>> v imenu Mohr, Rick via lustre-discuss <<a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a>><br class=""> Poslano: torek, 06. april 2021 16:34<br class=""> Za: Makia Minich <<a href="mailto:makia@systemfabricworks.com" class="">makia@systemfabricworks.com</a>>; <a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a> <<a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a>><br class=""> Zadeva: Re: [lustre-discuss] [EXTERNAL] ZFS and OST Space Difference <br class=""><br class=""> Makia,<br class=""><br class=""> 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?<br class=""><br class=""> --Rick<br class=""><br class=""> On 4/6/21, 3:49 PM, "lustre-discuss on behalf of Makia Minich" <<a href="mailto:lustre-discuss-bounces@lists.lustre.org" class="">lustre-discuss-bounces@lists.lustre.org</a> on behalf of <a href="mailto:makia@systemfabricworks.com" class="">makia@systemfabricworks.com</a>> wrote:<br class=""><br class=""> I believe this was discussed a while ago, but I was unable to find clear answers, so I\u2019ll re-ask in hopefully a slightly different way.<br class=""> On an OST, I have 30 drives, each at 7.6TB. I create 3 raidz2 zpools of 10 devices (ashift=12):<br class=""><br class=""> [root@lustre47b ~]# zpool list<br class=""> NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT<br class=""> oss55-0 69.9T 37.3M 69.9T - - 0% 0% 1.00x ONLINE -<br class=""> oss55-1 69.9T 37.3M 69.9T - - 0% 0% 1.00x ONLINE -<br class=""> oss55-2 69.9T 37.4M 69.9T - - 0% 0% 1.00x ONLINE -<br class=""> [root@lustre47b ~]#<br class=""><br class=""><br class=""> Running a mkfs.lustre against these (and the lustre mount) and I see:<br class=""><br class=""> [root@lustre47b ~]# df -h | grep ost<br class=""> oss55-0/ost165 52T 27M 52T 1% /lustre/ost165<br class=""> oss55-1/ost166 52T 27M 52T 1% /lustre/ost166<br class=""> oss55-2/ost167 52T 27M 52T 1% /lustre/ost167<br class=""> [root@lustre47b ~]#<br class=""><br class=""><br class=""> Basically, we\u2019re 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?<br class=""><br class=""> Thanks.<br class=""><br class=""> \u2014<br class=""><br class=""><br class=""> Makia Minich<br class=""><br class=""> Chief Architect<br class=""><br class=""> System Fabric Works<br class=""> "Fabric Computing that Works\u201d<br class=""><br class=""> "Oh, I don't know. I think everything is just as it should be, y'know?\u201d<br class=""> - Frank Fairfield<br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class=""><br class=""> _______________________________________________<br class=""> lustre-discuss mailing list<br class=""> <a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a><br class=""> <a href="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=" class="">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=</a> <br class=""><br class=""><br class=""> _______________________________________________<br class=""> lustre-discuss mailing list<br class=""> <a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a><br class=""> <a href="http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org" class="">http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org</a><br class=""><br class=""><br class=""><br class=""><br class=""><br class="">_______________________________________________<br class="">lustre-discuss mailing list<br class=""><a href="mailto:lustre-discuss@lists.lustre.org" class="">lustre-discuss@lists.lustre.org</a><br class="">http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org<br class=""></div></div></blockquote></div><br class=""></body></html>