On Thu, 03 Mar 2011 18:12:25 -0500 Jon LaBadie <[email protected]> wrote:
> I meant that with sarcasm, hope it came through.
;)
> I'd wager you wouldn't be able to differentiate using an LTO-2
> tapetype definition using 0KB vs 207KB filemarks.
Hmm...
> Unless things have changed, amanda uses the filemark in calculations
> like:
[...]
> In my limited experience with various tape formats and tapetype,
> I found my LTO-1 drive to give virtually identical results each
> run across different individual tapes and 2 brands of tape. The
> filemark was always 0. In contrast, my tapetype results for DAT
> (DAT-2 and DAT-3) were a bit inconsistant and showed definite
> differences between brands.
Interesting.
>
> If my amtapetype results showed a significant filemark while
> others generally report zero filemark for LTO formats, I'd ponder,
> but wouldn't worry too much, why I got my results.
Well, that's why I'm asking...all the entries for LTO-2 drive in wiki
have filemark 0k.
> I'd certainly rerun amtapetype. It not that big a hassle. You
> could have done that before asking and had your result before any
> replies to your query.
That's what I'm doing now, but it takes some time...
> I'd also look at the reported throughput. Amanda makes no use of
> the speed results; those are for your info only.
OK.
> I'd compare my observed results with other reports and with the
> drive manu- facturer's specified speed. If your system is unable to
> feed your drive data at a rate sufficient to keep it streaming, I'm
> pretty sure that apparent capacity and filemark can be affected.
The speed which I got (22522 kps) is in the boundary of other's
results) in the wiki as well ac close to HP's spec of 24Mps.
Now I'm doing test with compression disabled.
Here is the result:
Checking for FSF_AFTER_FILEMARK requirement
Applying heuristic check for compression.
Wrote random (uncompressible) data at 21864712.2580645 bytes/sec
Wrote fixed (compressible) data at 21864712.2580645 bytes/sec
Compression: disabled
Writing one file to fill the volume.
Wrote 203994431488 bytes at 22497 kb/sec
Got LEOM indication, so drive and kernel together support LEOM
Writing smaller files (2039939072 bytes) to determine filemark.
define tapetype unknown-tapetype {
comment "Created by amtapetype; compression disabled"
length 199213312 kbytes
filemark 208 kbytes
speed 22497 kps
blocksize 32 kbytes
}
# for this drive and kernel, LEOM is supported; add
# device-property "LEOM" "TRUE"
# for this device.
which shows that the drive is behaving even (slightly) better with
compression enabled. :-)
Sincerely,
Gour
--
“In the material world, conceptions of good and bad are
all mental speculations…” (Sri Caitanya Mahaprabhu)
http://atmarama.net | Hlapicina (Croatia) | GPG: CDBF17CA
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