Info Needed

[rajeshbahl]

1.The /etc/fstab file has following entries in addition to the entries for filesystems that are actually present:-

none /dev/pts devpts gid=5,mode=620 0 0
none /dev/shm tmpfs defaults 0 0


What do these entries signify ?

2. What is journaling in Red Hat Linux 7.3 ?


Thanks In Advance
Rajesh K. Bahl

 

[Morsing]

/dev/pts is the new type of device file system.
/dev/shm is a shared memory filesystem that you most likely don't need. I'm not sure which programmes uses it.

A journaling file system keeps track of meta data it is about to update on the disk. In case of a crash it can quickly recover the filesystem again by going through the log and committing the lost metadata.

Cheers Henrik Morsing
IBM Certified AIX 4.3 Systems Administration

 

[yzenezy]

The kernel documentation (on red hat /usr/src/linux/Documentation) can give you more information. Look in Documentation/devices.txt for /dev/pts and Documentation/filesystems/tmpfs for /dev/shm.

/dev/pts is a filesystem like proc to handle pseudo terminal slaves which help handle connections to your system (ssh for example)

/dev/shm is for shared memory handling. This is a new way of handling shared memory in kernel 2.4.x so not many programs are using it. For forward compatability you may want to keep this entry (some programs already use it).