https://jira.whamcloud.com This file is an XML representation of an issue en-us 9.4.14 940014 05-12-2023 https://jira.whamcloud.com/browse/LU-15437 Lustre <p>extend procfs to let lctl set_param add FLDB entries:</p> <div class="code panel" style="border-width: 1px;"><div class="codeContent panelContent"> <pre class="code-java"> [root@tmp tests]# lctl set_param fld.srv-lustre-MDT0000.fldb=[0x0000000280000400-0x0000000290000400]:0:mdt fld.srv-lustre-MDT0000.fldb=[0x0000000280000400-0x0000000290000400]:0:mdt [root@tmp tests]# lctl set_param fld.srv-lustre-MDT0000.fldb=[0x00000002a0000400-0x00000002b0000400]:2:ost fld.srv-lustre-MDT0000.fldb=[0x00000002a0000400-0x00000002b0000400]:2:ost [root@tmp tests]# lctl get_param fld.*.fldb fld.srv-lustre-MDT0000.fldb= [0x000000000000000c-0x0000000100000000]:0:mdt [0x0000000200000002-0x0000000200000003]:0:mdt [0x0000000200000007-0x0000000200000008]:0:mdt [0x0000000200000400-0x0000000240000400]:0:mdt [0x0000000280000400-0x0000000290000400]:0:mdt [0x00000002a0000400-0x00000002b0000400]:2:ost </pre> </div></div> LU-15437

setparam to modify fldb

Improvement Minor Open Unresolved WC Triage Alex Zhuravlev Tue, 11 Jan 2022 17:12:08 +0000 Mon, 21 Feb 2022 19:11:41 +0000 0 4 <p>"Alex Zhuravlev &lt;bzzz@whamcloud.com&gt;" uploaded a new patch: <a href="https://review.whamcloud.com/46042" class="external-link" target="_blank" rel="nofollow noopener">https://review.whamcloud.com/46042</a><br/> Subject: <a href="https://jira.whamcloud.com/browse/LU-15437" title="setparam to modify fldb" class="issue-link" data-issue-key="LU-15437">LU-15437</a> fld: extend procfs to allow fldb manipulations<br/> Project: fs/lustre-release<br/> Branch: master<br/> Current Patch Set: 1<br/> Commit: 8b938c541f844e0778e95ff6bf5d1095bb3b2c35</p> <p>I realized that there is <b>already</b> a way to recover the FLDB file with the existing code, since patch <a href="http://review.whamcloud.com/7027" class="external-link" target="_blank" rel="nofollow noopener">http://review.whamcloud.com/7027</a> "<tt><a href="https://jira.whamcloud.com/browse/LU-3565" title="HSM: Allow specifying minimum FID sequence at format time" class="issue-link" data-issue-key="LU-3565"><del>LU-3565</del></a> mdt: a new param to allocate sequences</tt>" was landed in v2_4_54.</p> <p>The code is confusing because there is "<tt>lustre/fid/lproc_fid.c</tt>" which is the <tt>seq.ctl-&#42;.fldb</tt> SEQ controller, and a separate "<tt>lustre/fld/lproc_fld.c</tt>" which is the individual <tt>fld.srv-&#42;.fldb</tt> SEQ servers (and cannot be written without your patch).</p> <p>The other thing that is broken is that <tt>seq.ctl-&#42;.fldb</tt> <b>prints</b> an entry like:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre> [0x0000000200000400-0x0000000240000400]:0:mdt </pre> </div></div> <p>but <b>reads</b> an entry like:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre> [0x0000000200000400-0x0000000240000400):0:mdt </pre> </div></div> <p>so it isn't possible to directly restore an existing <tt>fldb</tt> backup. Also, it must be written one entry at a time and in seq order. I'm working on a patch to fix that to be symmetrical.</p> <p>It also <em>appears</em> that there is a way to change the allocation range for a target, by writing:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>mds# lctl get_param seq.srv-testfs-MDT0000.space [0x200000bd0-0x240000000] mds# lctl set_param seq.srv-testfs-MDT0000.space="[0x201000000-0x240000000]" seq.srv-testfs-MDT0000.space=[0x201000000-0x240000000] mds# lctl get_param seq.srv-testfs-MDT0000.space [0x201000000-0x240000000] </pre> </div></div> <p>so this <b>looks</b> like it works, but in fact it does not affect sequence allocation for the current mount, nor does it modify the on-disk <tt>seq_srv</tt> file, whether the client and/or server are remounted:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>client# mount -t lustre centos7:/testfs /mnt/testfs2 touch /mnt/testfs2/foo; lfs path2fid /mnt/testfs/foo [0x200000bd4:0x1:0x0] mds# umount /mnt/testfs-mds2; mount -t lustre /dev/mapper/mds1_flakey /mnt/testfs-mds2 mds# lctl get_param seq.srv-testfs-MDT0000.space [0x2000013a0-0x240000000] client# umount /mnt/testfs2; mount -t lustre centos7:/testfs /mnt/testfs2 rm /mnt/testfs2/foo; touch /mnt/testfs2/foo; lfs path2fid /mnt/testfs/foo [0x2000013a0:0x1:0x0] </pre> </div></div> <p>Note also that if the on-disk <tt>seq_srv</tt> value is wrong this triggers an <tt>LASSEERT</tt> from the on-disk data (which happened to me as I was testing things), which isn't helpful. Better to return an error and fail the mount:</p> <div class="preformatted panel" style="border-width: 1px;"><div class="preformattedContent panelContent"> <pre>LustreError: 18161:0:(fid_handler.c:579:seq_server_init()) ASSERTION( lu_seq_range_is_sane(&amp;seq-&gt;lss_space) ) failed: [21797.990017] LustreError: 18161:0:(fid_handler.c:579:seq_server_init()) LBUG </pre> </div></div> Related LU-3565 LU-15414 LU-15580 Development Rank 1|i02ee7: Rank (Obsolete) 9223372036854775807