LU-6937 test: use ps in get_agent_uuid()

[fs/lustre-release.git] / Documentation / lfsck.txt

diff --git a/Documentation/lfsck.txt b/Documentation/lfsck.txt
index 246fcb1..2b42d19 100644 (file)
--- a/Documentation/lfsck.txt
+++ b/Documentation/lfsck.txt
@@ -163,9 +163,12 @@ osd-ldiskfs.<fsname>-<targetname>.full_scrub_threshold_rate). On starting, the
 master engine sends RPCs to other MDTs (when necessary) to start other master
 engines and to related OSTs to start the slave engines.
 
 master engine sends RPCs to other MDTs (when necessary) to start other master
 engines and to related OSTs to start the slave engines.
 

-2. The master engine on the MDT scans the MDT local device. Each object is
-checked for the consistency criteria enumerated in the 'features' section of
-this document.
+2. The master engine on the MDS scans the MDT device using namespace iteration
+(described below). For each striped file, it calls the registered LFSCK process
+handlers to perform the relevant system consistency checks/repairs, which are
+enumerated in the 'features' section. All objects on OSTs that are never
+referenced during this scan (because, for example, they are orphans) are
+recorded in an OST orphan object index on each OST.

 
 3. After the MDT completes first-stage system scanning, the master engine sends
 RPCs to related LFSCK engines on other targets to notify that the first-stage
 
 3. After the MDT completes first-stage system scanning, the master engine sends
 RPCs to related LFSCK engines on other targets to notify that the first-stage


@@ -194,10 +197,10 @@ Orphan objects will either be relinked to an existing file if found - or moved
 into a new file in .lustre/lost+found.
 
 If multiple MDTs are present, MDTs will check/repair MDT-OST consistency in
 into a new file in .lustre/lost+found.
 
 If multiple MDTs are present, MDTs will check/repair MDT-OST consistency in

-parallel. To avoid scans of the OST device the slave engine will not begin
-second-stage system scans until all the master engines complete the first-stage
-system scan. For each OST there is a single OST orphan object index, regardless
-of how many MDTs are in the MDT-OST consistency check/repair.
+parallel. To avoid redundant scans of the OST device the slave engine will not
+begin second-stage system scans until all the master engines complete the
+first-stage system scan. For each OST there is a single OST orphan object
+index, regardless of how many MDTs are in the MDT-OST consistency check/repair.

 
 
 Object traversal design reference
 
 
 Object traversal design reference


@@ -263,21 +266,21 @@ useful links:      http://insidehpc.com/2013/05/02/video-lfsck-online-lustre-fil
 Glossary of terms
 ===============================================
 
 Glossary of terms
 ===============================================
 

-OSD - Object storage device. A generic term for a storage device with an
-  interface that extends beyond a block-oriented device interface.
-

 FID - File IDentifier. A Lustre file system identifies every file and object
   with a unique 128-bit ID.
 
 FID - File IDentifier. A Lustre file system identifies every file and object
   with a unique 128-bit ID.
 

-OI - Object Index. A table that maps the FID to the object's backend identifier.
-  For ldiskfs-based backend, this table must be regenerated if restored from
-  file-level backup.
-

 FID-in-dirent - FID in Directory Entry. To enhance the performance of readdir,
   the FID of a file is recorded in its directory name entry.
 
 FID-in-dirent - FID in Directory Entry. To enhance the performance of readdir,
   the FID of a file is recorded in its directory name entry.
 

+linkEA - Link Extended Attributes. When a file is created or hard-linked the
+  parent directory name and FID are recorded as extended attributes to the file.
+

 LMA - Lustre Metadata Attributes. A record of Lustre specific attributes, for
   example HSM state, self-FID, and so on.
 
 LMA - Lustre Metadata Attributes. A record of Lustre specific attributes, for
   example HSM state, self-FID, and so on.
 

-linkEA - Link Extended Attributes. When a file is created or hard-linked the
-  parent directory name and FID are recorded as extended attributes to the file.
+OI - Object Index. A table that maps FIDs to inodes. On ldiskfs-based targets,
+  this table must be regenerated if a file level restore is performed as inodes
+  will change.
+
+OSD - Object storage device. A generic term for a storage device with an
+  interface that extends beyond a block-oriented device interface.