LaValley, Brian E wrote:
Good point, my tape drive maximum sustained data transfer rate is 60 MBytes
per second on a Gigabit ethernet network. Is that too slow?
Maybe. Maybe not.
Those modern drives sometimes (usually) slow down their motors when
the bytes do not flow in fast enough, so that they keep streaming, but
only at a lower speed.
Even gigabit ethernet cannot do 120 Mbytes/sec, or 60MB/sec full duplex.
To find out how amanda gets the numbers, you may download the sources
of amanda, do a complete configure and compile ("make install" not
needed), and create a little standalone program "statfs", like this:
$ ./configure --with-user=... etc. (not necessary to get
everyting completely correct, you don't
need to do a "make install"; compile should
succeed, of course)
$ make
$ cd common-crc
$ make statfs
And now run the standalone "statfs" on those filesystems.
It will show what kind of statfs call it uses, and the values of
the different fields the OS gives back.
e.g.
$ /tmp/quick/amanda-2.4.5/common-src/statfs .
statfs (SVR4 (Irix-5+, Solaris-2, Linux glibc 2.1))
name total free avail files ffree favail
--------------- ------- ------- ------- ------ ------ ------
. 129015488 83820512 77266912 16384000 16137345 16137345
As you can see, there is sometimes a difference between "free" and
"avail". I'm not sure why... probably the reserved space in the
filesystem. Amcheck uses the "avail" value.
My "df" is consistent:
$ df -k .
Filesystem 1k-blocks Used Available Use% Mounted on
xlate:/space/tm 129015488 45194976 77266912 37% /net/xlate/tm
Amcheck produces:
Amanda Tape Server Host Check
-----------------------------
WARNING: holding disk /backup/amanda/dumps/dump2: only 88344348 KB free
(104857600 KB requested)
WARNING: holding disk /backup/amanda/: only 8842796 KB free (26214400 KB
requested)
amcheck-server: slot 0: date X label DailySet1-A00 (new tape)
NOTE: skipping tape-writable test
Tape DailySet1-A00 label ok
Server check took 690.657 seconds
Amanda Backup Client Hosts Check
--------------------------------
Client check: 1 host checked in 0.063 seconds, 0 problems found
(brought to you by Amanda 2.4.4p2)
The NFS mount is /backup/amanda/dumps/dump2. "df" produces:
Filesystem 1K-blocks Used Available Use% Mounted on
jhaas-l:/native/amanda 207955672 25107104 172285032 13%
/backup/amanda/dumps/dump2
So in reality, there is 172GB free and Amanda only sees 88GB free.
What is the 32 bit long size you mention in amanda?
Amanda internally uses a signed 32bit long, which holds the size
in units of 1 Kbyte. That means such variable can hold values
up to 1024 * 2^31 bytes, or about 2 TByte.
--
Paul Bijnens, Xplanation Tel +32 16 397.511
Technologielaan 21 bus 2, B-3001 Leuven, BELGIUM Fax +32 16 397.512
http://www.xplanation.com/ email: Paul.Bijnens AT xplanation DOT com
***********************************************************************
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