69 lines
3.9 KiB
Plaintext
69 lines
3.9 KiB
Plaintext
|
WHAT IS AMANDA?
|
||
|
|
---------------
|
||
|
|
|
||
|
|
This is an alpha-test release of Amanda, the Advanced Maryland Automatic
|
||
|
|
Network Disk Archiver. Amanda is a backup system designed to archive many
|
||
|
|
computers on a network to a single large-capacity tape drive. This release
|
||
|
|
is currently in daily use at the University of Maryland at College Park
|
||
|
|
Computer Science Department, backing up all the disks on all the
|
||
|
|
workstations in the department: currently over 70 gigabytes of data across
|
||
|
|
more than 400 filesystems on more than 146 workstations and servers, using
|
||
|
|
a single 5 Gigabyte Exabyte EXB-8500. Here are some features of Amanda:
|
||
|
|
|
||
|
|
* written in C, freely distributable.
|
||
|
|
* built on top of standard backup software: BSD Unix dump/restore, and
|
||
|
|
later GNU Tar and others.
|
||
|
|
* will back up multiple machines in parallel to a holding disk, blasting
|
||
|
|
finished dumps one by one to tape as fast as we can write files to
|
||
|
|
tape. For example, a ~2 Gb 8mm tape on a ~240K/s interface to a host
|
||
|
|
with a large holding disk can be filled by Amanda in under 4 hours.
|
||
|
|
* does simple tape management: will not overwrite the wrong tape.
|
||
|
|
* supports tape changers via a generic interface. Easily customizable to
|
||
|
|
any type of tape carousel, robot, or stacker that can be controlled via
|
||
|
|
the unix command line.
|
||
|
|
* supports Kerberos 4 security, including encrypted dumps. The Kerberos
|
||
|
|
support is available as a separate add-on package, see the file
|
||
|
|
KERBEROS.HOW-TO-GET on the ftp site, and the file docs/KERBEROS in this
|
||
|
|
package, for more details.
|
||
|
|
* for a restore, tells you what tapes you need, and finds the proper
|
||
|
|
backup image on the tape for you.
|
||
|
|
* recovers gracefully from errors, including down or hung machines.
|
||
|
|
* reports results, including all errors in detail, in email to operators.
|
||
|
|
* will dynamically adjust backup schedule to keep within constraints: no
|
||
|
|
more juggling by hand when adding disks and computers to network.
|
||
|
|
* includes a pre-run checker program, that conducts sanity checks on both
|
||
|
|
the tape server host and all the client hosts (in parallel), and will
|
||
|
|
send an e-mail report of any problems that could cause the backups to
|
||
|
|
fail.
|
||
|
|
* can compress dumps before sending over net, with either compress or gzip.
|
||
|
|
* can optionally syncronize with external backups, for those large
|
||
|
|
timesharing computers where you want to do fu--------------------------------------------
|
||
|
|
|
||
|
|
Amanda requires a host that is mostly idle at night, with a large capacity
|
||
|
|
tape drive (e.g. an EXABYTE or DAT tape). This becomes the "tape server
|
||
|
|
host". All the computers you are going to dump are the "backup client
|
||
|
|
hosts". The server host can also be a client host.
|
||
|
|
|
||
|
|
Amanda works best with one or more large "holding disk" partition on the
|
||
|
|
server host available to it for buffering dumps before writing to tape.
|
||
|
|
The holding disk allows Amanda to run backups in parallel to the disk, only
|
||
|
|
writing them to tape when the backup is finished. Note that the holding
|
||
|
|
disk is not required: without it Amanda will run backups sequentially to
|
||
|
|
the tape drive. Running it this way kills the great performance, but still
|
||
|
|
allows you to take advantage of Amanda's other features.
|
||
|
|
|
||
|
|
As a rule of thumb, for best performance the holding disk should be larger
|
||
|
|
than the dump output from your largest disk partitions. For example, if
|
||
|
|
you are backing up some full gigabyte disks that compress down to 500 MB,
|
||
|
|
then you'll want 500 MB on your holding disk. On the other hand, if those
|
||
|
|
gigabyte drives are partitioned into 500 MB filesystems, they'll probably
|
||
|
|
compress down to 250 MB and you'll only need that much on your holding
|
||
|
|
disk. Amanda will perform better with larger holding disks. We use 800 MB
|
||
|
|
for our holding disk.
|
||
|
|
|
||
|
|
Actually, Amanda will still work if you have full dumps that are larger
|
||
|
|
than the holding disk: Amanda will send those dumps directly to tape one at
|
||
|
|
a time. If you have many such dumps you will be limited by the dump speed
|
||
|
|
of those machines.
|
||
|
|
|