Hello Karsten, Gene, all,

Gene Heskett wrote:

On Saturday 20 December 2003 02:30, Georg Rehfeld wrote:

Hallo Karsten, dear Amanda users,

i am wondering if it is possible to check how much data is already
written in the curent run of amdump/amflush.

In the output of amstatus is just an overwiev per filesystem, but
i am interested how much of that particular filesystem is already
on tape and for example the estimated time.

... advertisement about amstatus.cgi cut ...

But: amstatus, while a backup is running
- CAN look at the file size of the holding disk files, even when
they are just written, with some error, sure, but good enough for a
valuable estimate most of the time.
- CAN estimate (very rough) times of dumps done directly to tape
  from calculations of average dump/tape speed and the estimated
  size of the dump. This may be _very_ rough, as stop/rewind/start
times of a tape not streaming are simply unknown to amanda at all.

Yes, this would be the great unknown if the machine is so slow as to not be able to keep the drive streaming. Certainly not a problem here with a 400k/sec drive and a 1450mhz machine. But, given the write speed obtained on those disklist entries that have been finished, it seems to me that a reasonable estimate of the current files progress, based on current time-start time and that transfer rate, could be guessed at and displayed.

That would not take any mods to amanda. :-)

I just found out, that amdump files already contain estimates about
the time needed to dump each filesystem. They are in the GENERATING
SCHEDULE: section in the DUMP lines, the 10th value is the estimated
dump time in seconds. The Amanda planner uses collected statistics
from previous dumps for this, if available, else uses a default
dump rate for calculation.

Unless the default must be used the esimated times are very near
to reality, far better than all estimating possible from other values
available to amstatus. amstatus did not use these times so far.

For display of progress in % and time to finish a dump I will use
these times (in the CGI part only for now).

There seem to be no similar figures for taping and the tape speed
seems to vary largely:

size  speed    speed
  MB   MB/s    graph

 102    1.8    *******
 108    2.0    ********
 113    1.7    *******
 141    2.4    **********
 227    1.9    ********
 228    2.1    ********
 251    1.0    ****
 253    2.1    ********
 292    7.0    ****************************
 294    1.9    ********
 328    3.2    *************
 339    1.9    ********
 450    2.9    ************
 473    4.0    ****************
 587    3.4    *************
 590    5.5    **********************
 837    4.7    *******************
1029    2.4    **********
3132    6.5    **************************
3456    8.6    **********************************
3512    7.4    ******************************

(All sizes reasonable large, all taping done from holding disk, all
values from one backup run)

The ratio of tape speeds is nearly 1:9, a tendency is: larger files
tape faster, when looking at only sizes > 500 MB the ratio is only
1:3.6

Thus estimating tape time/percentage remains to be _very_ rough IMO
without modifying Amanda to write taper progress to the amdump file,
when taping from holding disk.

When taping directly from partition, the situation might be much better:

where the dumper must wait for the tape. This is what I believe, though
I havn't verified it enough to be sure.

regards

Georg
--
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| + | |__    Georg Rehfeld      Woltmanstr. 12     20097 Hamburg
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