3.5.1 Matrix Server Administration Guide

Chapter 7: Configure PSFS Filesystems 96

Crash Recovery

When a server using a PSFS filesystem either crashes or stops

communicating with the matrix, another server in the matrix will replay

the filesystem journal to complete any transactions that were in progress

at the time of the crash.

Users on the remaining servers will notice a slight delay while the journal

is replayed. Typically the recovery procedure takes only a few seconds.

The recovery process restores only the structural metadata information.

Any regular file data in the blocks that were in use when the crash

occurred may be corrupted or lost.

The server that crashed or lost communication with the matrix will not be

able to access the filesystem until it is rebooted.

Filesystem Quotas

The PSFS filesystem supports hard and soft quotas for users and groups.

A hard quota specifies the maximum amount of disk space in a particular

filesystem that can be used by files owned by the user or group. A soft

limit is typically set below the hard limit and triggers a warning when it

is reached.

Quotas are enabled or disabled at the filesystem level. When quotas are

enabled, the filesystem performs quota accounting to track the disk use of

each user or group having an assigned disk quota. When a file owner

reaches the hard limit, the filesystem will not allow the owner to create

files or increase the size of an existing file; any attempts to allocate more

space will fail. The file owner will need to remove files or reduce their

size until the disk usage falls below the hard limit.

When you create a filesystem with quotas enabled, you can set default

hard limits for users and groups. These limits apply to all users and

groups on the filesystem; however, you can change the limit for specific

users or groups. You can also set a soft limit for users or groups.

For more information about managing disk quotas for individual users

and groups, see “Manage Filesystem Quotas” on page 175.