Change /var/avamar/cache default directory.
EMC Avamar client uses two file for tracking the changes on the file system to ease the backups with de-duplication.
At the beginning of the backup avtar loads up into memory two files from the VAR directory:
fcache.dat and pcache.dat
The f_cache.dat cache file stores a 20-byte SHA-1 hash of the file attributes, and is used to quickly identify which files have previously been backed up to the Avamar server.
The p_cache.dat hash cache stores the hashes of the chunks and composites that have been sent to the Avamar server. The hash cache is used to quickly identify which chunks or composites have previously been backed up to the Avamar server. The hash cache is very important when backing up databases.
By default, the maximum File Cache size can be 1/8 of the RAM and the maximum Hash Cache size will 1/16 of the RAM.
Because the avtar program is a 32-bit application, the maximum file cache size that avtar can use is limited to less than 2 GB. In an example where a client has 4 GB of RAM, the maximum size of the file cache is 352 MB.
Each entry in a file cache comprises a 4-byte header plus two 20-byte SHA-1 hashes (44 bytes total):
SHA-1 hash entry of the file attributes. The file attributes include: file name, file path, modification time, file size, owner,group, and permissions.
SHA-1 hash entry for the hash of the actual file content, independent of the file attributes.
In machines with a huge amount of RAM and scenarios very limited local disk size where the Avamar Client has been installed, you may ran out of space.
You may then present a new LUN, disk, NFS mount etc to your server and change the Avamar Cache folder from default /var to any you prefer.
To do so you can use the flag in the avtar.cmd file as follows:
[root@NFSEC ~]# cat /var/avamar/avtar.cmd --cachedir=/home/avamarcache