Preventing disk thrashing in Amanda Enterprise

  • This article is for Amanda Enterprise (AE)

Using spindle numbers in the disklist.conf to prevent disk thrashing

When backing up multiple DLEs simultaneously its important to consider performance. Performance will be greatly affected if multiple DLE are being backed up simultaneously from the same physical disk in conjunction with using a “holding disk”. Amanda enables a solution to this problem utilizing “spindle numbers”.

“spindle number”

Field four of the disklist file is a spindle number. Areas with the same spindle number are not backed up at the same time. This prevents thrashing on an individual physical disk. The disklist.conf file is located on the server at /etc/amanda/<backup set>/disklist.conf.

Field1-Hostname Field2-DLE Field3-Alias {[...]}Field4-Spindle

example.zmanda.com "/boot" "comp-user-tar" {
 [...]
}1

Example Scenario:

List of directories we want to backup on a client:

Physical Disk 1:

Filesystem Size Used Avail Use% Mounted on

/dev/md3 15G 3.1G 11G 22% /

/etc
/opt
/usr

Physical disk 2:

Filesystem Size Used Avail Use% Mounted on

/dev/md4 334G 175G 143G 56% /home

/home/ppragin
/home/amanda
/home/admin
/home/uploads

Physical disk 3 (dedicated holding disk):

Filesystem Size Used Avail Use% Mounted on

/dev/md2 159G 189M 151G 1% /holding

What your disklist.conf file should look like:

example.zmanda.com "/etc" "/etc" {
[...]
} 1

example.zmanda.com "/opt" comp-user-tar {
[...]
} 1

example.zmanda.com /usr comp-user-tar {
[...]
} 1

example.zmanda.com /lib comp-user-tar {
[...]
} 1

example.zmanda.com /home/ppragin comp-user-tar {
[...]
} 2

example.zmanda.com /home/amanda comp-user-tar {
[...]
} 2

example.zmanda.com /home/admin comp-user-tar {
[...]
} 2

example.zmanda.com /home/uploads comp-user-tar {
[...]
} 2

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