From 773e248248b010235840abeaadadff1cc9626378 Mon Sep 17 00:00:00 2001 From: Richard Henwood Date: Mon, 16 May 2011 15:36:38 -0500 Subject: [PATCH] FIX: converted to chapter and removed cruft --- LustreTroubleshooting.xml | 117 ++-------------------------------------------- 1 file changed, 3 insertions(+), 114 deletions(-) diff --git a/LustreTroubleshooting.xml b/LustreTroubleshooting.xml index fdb6145..57e7a5e 100644 --- a/LustreTroubleshooting.xml +++ b/LustreTroubleshooting.xml @@ -1,69 +1,8 @@ -
+ Lustre Troubleshooting - - - - - - - - - Lustre 2.0 Operations Manual - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - C H A P T E R  26 - - - - - - - - - - - Lustre Troubleshooting - - - - This chapter provides information to troubleshoot Lustre, submit a Lustre bug, and Lustre performance tips. It includes the following sections: Lustre Error Messages @@ -317,7 +256,7 @@
<anchor xml:id="dbdoclet.50438198_pgfId-1291436" xreflabel=""/>26.3.4 <anchor xml:id="dbdoclet.50438198_69657" xreflabel=""/>Fixing a Bad LAST_ID on an OST - Each OST contains a LAST_ID file, which holds the last object (pre-)created by the MDS The contents of the LAST_ID file must be accurate regarding the actual objects that exist on the OST. . The MDT contains a lov_objid file, with values that represent the last object the MDS has allocated to a file. + Each OST contains a LAST_ID file, which holds the last object (pre-)created by the MDS The contents of the LAST_ID file must be accurate regarding the actual objects that exist on the OST.. The MDT contains a lov_objid file, with values that represent the last object the MDS has allocated to a file. During normal operation, the MDT keeps some pre-created (but unallocated) objects on the OST, and the relationship between LAST_ID and lov_objid should be LAST_ID <= lov_objid. Any difference in the file values results in objects being created on the OST when it next connects to the MDS. These objects are never actually allocated to a file, since they are of 0 length (empty), but they do no harm. Creating empty objects enables the OST to catch up to the MDS, so normal operations resume. However, in the case where lov_objid < LAST_ID, bad things can happen as the MDS is not aware of objects that have already been allocated on the OST, and it reallocates them to new files, overwriting their existing contents. Here is the rule to avoid this scenario: @@ -598,57 +537,7 @@ LAST_ID" <anchor xml:id="dbdoclet.50438198_pgfId-1294801" xreflabel=""/>26.3.14 Setting SCSI <anchor xml:id="dbdoclet.50438198_marker-1294800" xreflabel=""/>I/O Sizes Some SCSI drivers default to a maximum I/O size that is too small for good Lustre performance. we have fixed quite a few drivers, but you may still find that some drivers give unsatisfactory performance with Lustre. As the default value is hard-coded, you need to recompile the drivers to change their default. On the other hand, some drivers may have a wrong default set. If you suspect bad I/O performance and an analysis of Lustre statistics indicates that I/O is not 1 MB, check /sys/block/<device>/queue/max_sectors_kb. If the max_sectors_kb value is less than 1024, set it to at least 1024 to improve performance. If changing max_sectors_kb does not change the I/O size as reported by Lustre, you may want to examine the SCSI driver code. - - - - - - - - - - - - - - Lustre 2.0 Operations Manual - 821-2076-10 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Copyright © 2011, Oracle and/or its affiliates. All rights reserved.
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+ -- 1.8.3.1