6.5 HP StoreAll OS User Guide

Online Metadata Synchronizer
The Online Metadata Synchronizer can be used to:
• Verify the consistency of the system metadata stored in Express Query database against the
metadata of the file system. Like the ibrix_fsck command, this task is useful when there is
a possibility of metadata inconsistencies between the file system and the Express Query
database. Such inconsistencies may arise from abnormal occurrences such as power outages,
system failures, truncated path names, or partial NDMP restores.
• Provide support for hard links by ensuring that, in the case of a file with multiple path names,
only one path name is used consistently in the database. The path name that is used is chosen
by the system. For more information about hard links, see “Express Query and special files”
(page 308).
• Restore path names if the maximum number of directory rename operations has been exceeded.
For more information about this issue, see “Troubleshooting an Express Query Manual
Intervention Failure (MIF)” in the administrator guide for your platform.
By default, Online Metadata Synchronizer is run weekly on Sundays at 2:30 a.m. The amount of
time it takes to execute the Online Metadata Synchronizer is proportional to the number of files in
the file system. It will put some I/O load on the segment servers in the file system and also consume
CPU and memory on the active Fusion Manager node. You may want to change the schedule to
a date and time when you expect reduced activity in the file system. For example, if you have a
file system containing one billion files, HP recommends moving the Online Metadata Synchronizer
schedule to a monthly task. For information about changing the Online Metadata Synchronizer
schedule, see the ibrix_archiving command in the HP StoreAll OS CLI Reference Guide.
Express Query and special files
There are several types of special files and Express Query support for these files varies. The following
table lists the types of special files and how they work with Express Query.
Express Query supportFile type
System metadata is updated, but Express Query cannot initially track when the file is
renamed or moved. For example, you have a file named char_file in the dir1/dir2
Character device file
Block device file
directory structure (dir1/dir2/char_file). If you rename char_file to
char_file1 or change the directory the file is in, only the original path and file name
FIFO file
(dir1/dir2/char_file) is maintained in the database. However, once the Online
Synchronizer is run, any changes will be updated in the database.
Socket file
You cannot assign custom metadata to these files.
System metadata is updated, except for the path name. Only one path name is stored in
the database and it can be any one of the multiple path names to the inode. For example,
Hard link
if you have a file with two hard links (a/b/file and a /file2), then queries for the file
path name may return either a/b/file or a /file2. Assigning custom metadata to
multiple linked inodes will not fail, but query results may be inconsistent (some or all of
the custom metadata is returned).
You can use the Online Metadata Synchronizer to enforce a single path name from a
multiply linked file to be consistently used in the database (however, the path name that
is used is chosen by the system).
System metadata is updated. Custom metadata is assigned to the file to which the symlink
points, not directly to the symlink.
Symlink (Symbolic link)
Express Query Windows Search Integration (EQWSI)
The Express Query Windows Search Integration (EQWSI) feature in StoreAll lets you use metadata
to retrieve information quickly from your file records on the HP StoreAll file system from an EQWSI
supported Windows client without logging into any cluster nodes.
308 Express Query