6.12.5 Other Notes

In online processing for Fsystem, fsck may be executed.
If fsck is executed during Online processing, the processing may not be completed within time set with ScriptTimeout. As a result, the startup or switchover processing fails.
To use Fsystem, set the ScriptTimeout value that the processing time of fsck is considered.

Do not access mountpoint specified in Fsystem from other than a userApplication.
During Offline processing, if accessing the mountpoint specified in Fsystem with other process, the Offline processing may fail and a switchover may not be performed.

Do not change the mountpoint name for Fsystem with such as mv command when a userApplication is Online.
If the mountpoint name is changed when Online, hvdet_gmount detects an error and a userApplication is switched. To change the mountpoint name temporarily, stop RMS first.

If 31 or more mountpoints registered in a single Fsystem resource exist, you need to change the default timeout value (180 seconds).
For the Timeout value of the Fsystem resource, "the number of mountpoints registered in single Fsystem x 6 seconds" or more needs to be set.
For example, if 31 mountpoints are registered in a single Fsystem resource, set "31 x 6 seconds = 186 seconds" or more to the Timeout attribute of the Fsystem resource.
The timeout value set in each Fsystem resource is the time until all processing completes for the mountpoints registered in the Fsystem resource.
For example, if three mountpoints; /mnt1, /mnt2, and /mnt3 are registered in the Fsystem resource, and also 100 seconds is set to the timeout value, the processing times out unless the processing of all three mountpoints completes within 100 seconds.
For the disk partition used in the Fsystem resource, it is necessary to create beforehand.
If it has not been created, Online processing fails.
If a shared disk cannot be accessed, double fault may occur.
If a shared disk cannot be accessed, the Fsystem resource becomes Faulted. In this case, mountpoints cannot be unmounted in Offline processing (this processing is conducted after Faulted processing), and then double fault may occur.
Prevent the forced file system check from being executed.
If ext3 is used for a file system, the file system might forcibly be checked during online processing of a switching file system. It is part of the ext3 specification that file systems are checked when a certain number of mounting has been executed since the last file system check, or a certain period of time has passed.
When the file systems are forcibly checked along with node startup or switchover, a timeout occurs due to file system online processing, and PRIMECLUSTER startup or switchover may fail.
To prevent this situation, execute the following command for all the ext3 switching files so that the forcible file system check will not be executed.
```
# tune2fs -c0 -i0 <device_name>
```
Example
```
# tune2fs -c0 -i0 /dev/sdi1
```
After executing the above command, check if "Maximum mount count :-1" and "Check interval:0"are displayed using the following command.
```
# tune2fs -l /dev/sdi1
[snip]
Mount count: 10
Maximum mount count: -1
[snip]
Check interval: 0 (<none>)
[snip]
```
If the forcible file system check is prevented, file systems might corrupt due to failures such as disk errors and kernel bug. These failures cannot be detected through file system logging and journaling. The file system corruption might cause data corruption. To prevent this, execute the "fsck - f" command to enable the file system forcible check during periodic maintenance.
Using ext4 for a file system on a share disk device
The ext4 file system is available after Red Hat Enterprise Linux 6.
For PRIMECLUSTER, It is recommended to use ext3 as a file system controlled by the Fsystem resource. If you use ext 4 on your requests, set the Delayed Allocation disabled.
Specify nodelalloc for the mount attribute of the /etc/fstab.pcl file.
Example
/etc/fstab.pcl file
```
#RMS#/dev/sfdsk/class0001/dsk/volume0002 /mnt/swdsk2 ext4 nodelalloc 0 0
```