[LUDOC-259] LFSCK4: Review the LFSCK documentation

• Status: Resolved
• Project: Lustre Documentation
• Type: Improvement
• Priority: Critical
• Reporter: Richard Henwood (Inactive)
• Assignee: nasf (Inactive)
• Resolution: Fixed

Description

Review the whole of the LFSCK documentation in the manual to ensure it is fit for purpose.

Issue Links

• is related to: LUDOC-369 update backup/restore documentation
• is related to: LUDOC-186 Document OI Restoration
• is related to: LUDOC-145 LFSCK Phase 1.5 - Enable dirdata befo...

Comments

[Andreas Dilger]

After investigating LU-6265 I see that the /proc tunables and stats files are not really documented in the user manual. That should be done.

[Richard Henwood (Inactive)]

One patch landed to improve clarity: http://review.whamcloud.com/#/c/14692/

[Richard Henwood (Inactive)]

Now working on a patch for 'index_in_idif'.

[Richard Henwood (Inactive)]

From discussion with Fan Yong:

On Tue, 2015-12-08 at 02:32 +0000, Yong, Fan wrote:
> Yes, it is only for OST upgrade case (always use '0' as the index in
> IDIF, LU-3569). It depends on the sysadmin whether to enable OST-
> index in IDIF. Similar as FID-in-dirent, once it is enabled, it cannot
> be reverted. Means cannot downgrade.
>

Ok, which upgrade versions does it affect? 2.7->2.8?
or something different?

In fact, the patch of packing OST index into the IDIF has been landed since Lustre-2.6, but the patch for index_in_idif is landed to Lustre-2.7.

So the real upgrade case happened for any old OST 2.x (x <=5), but you only can control that for the new OST 2.y (y >=7). That means, if you update 2.5 to 2.6, you should store OST index in IDIF, but you cannot control that.

[Andreas Dilger]

The index_in_idif tunable was added for Lustre 2.7.0. It is used for improving the on-disk metadata information for ldiskfs OSTs after upgrade to increase the robustness of the LFSCK checking. OST filesystems formatted with Lustre 2.7.0 and later are already using the new on-disk metadata information and this tunable will not be present. For OST filesystems formatted with Lustre 2.4-2.6 that have not yet been upgraded, the index_in_idif tunable will be available to allow the one-time upgrade the new on-disk metadata information. Once this upgrade is completed, the system cannot easily be downgraded, so it should only be done after running the 2.7.0 or newer software for a long enough time that there is no chance of downgrade.

To check if the filesystem still needs to be upgraded, use lctl get_param osd-ldiskfs.*.index_in_idif on a Lustre 2.7.0 or newer OSS node. If this prints osd-ldiskfs.$fsname-OSTxxxx=0 for any OST, then the OST still needs to be upgraded. In order to enable the improved on-disk metadata information, use lctl set_param osd-ldiskfs.*.index_in_idif=1 on all OSS nodes in the filesystem. On the next remount of the filesystem the index_in_idif tunable will no longer be present.

[Andreas Dilger]

It may be that some of the linked LUDOC tickets have already been addressed in the manual, in which case they can be closed. Otherwise, please submit patches to the manual to address the gaps.

[Gerrit Updater]

Fan Yong ([e-mail]) uploaded a new patch: https://review.whamcloud.com/26028
Subject: LUDOC-259 lfsck: add the missed lfsck commands and options
Project: doc/manual
Branch: master
Current Patch Set: 1
Commit: eb025ea2ceb2ca518437f1fb07f8d4016bbaa0e7

[Gerrit Updater]

Joseph Gmitter ([e-mail]) merged in patch https://review.whamcloud.com/26028/
Subject: LUDOC-259 lfsck: add the missed lfsck command and option
Project: doc/manual
Branch: master
Current Patch Set:
Commit: f1e4fa7e73797c13a55d3de49bedfb9987e761d7

[nasf (Inactive)]

The patch has been landed.