Managing Systems and Workgroups: A Guide for HP-UX System Administrators

Administering a System: Managing Disks and Files
Managing File Systems
Chapter 6618
Once you have returned the files in the lost+found directory to their
proper locations, restore any files that are missing from your most recent
backup.
IMPORTANT The following message
CAN'T READ BLOCK ...
may indicate a media problem that mediainit (1) can resolve. Otherwise,
hardware failure has probably occurred; in this case, contact your local
sales and support office.
Checking a JFS File System fsck checks a JFS file system by using
an intent log to evaluate changes to the file system. The intent log
records all pending changes to the file system structure; that is, all
transactions the system intends to make to the file system prior to
actually doing the changes. A “replay” of the intent log is very fast and
may be no more time consuming for a large file system than a small one
because it is dependent on file system activity rather than file system
size. As a result, even in the event of a system failure, the system can be
up and running again very quickly.
In cases of disk failure, scanning the JFS intent log is insufficient; in
such instances, you will need to check the entire file system. Do this by
using the -o full option of fsck. For further information, refer to
fsck_vxfs (1M).
Differences between HFS and JFS File Checking Although from
an administrative perspective, using fsck to check and correct HFS and
JFS file systems is similar, some important differences are summarized
in Table 6-7.
Table 6-7 HFS vs. JFS File Checking after System Failure
Concern HFS JFS
What needs to
be checked?
The entire file system. This can be
time consuming. As the size of the
file system increases, the time
required for fsck will increase.
The intent log only. This may be
no more time consuming for a
large file system than a small one.