On Wed, Mar 12, 2014 at 02:38:48PM +0000, Dave Ewart wrote:
> Hello,
>
> Four years ago I deployed a pair of Tandberg LTO-5 Ultrium (SAS) tape,
> connected a Dell PowerEdge server via a Dell H200 SAS controller.
>
> At that time ran the amtapetype utility which produced this output:
>
> define tapetype Tandberg-LTO5 {
> comment "Tandberg LTO5 1500/3000, produced by tapetype prog (hardware
> compression off)"
> length 1410 gbytes
> filemark 0 kbytes
> speed 125762 kps
> }
>
> (That was created by an older version of AMANDA, which we were using at
> the time: probably from Debian/Lenny, which was version 2.5.2p1, I
> believe)
>
> These tapes are native 1.5TB and so that looks pretty reasonable. We've
> never used these tapes to their fullest capacity and all was fun and
> shiny until recently when the tapes reported "No space left on device".
> However, the concerning thing is that the tapes reported 'full' at less
> than what I was expecting as full capacity, just above 1.1TB in fact.
> This means that our backup space 'growth', which I had been assuming was
> only 75%/80% full is in fact at 100%!
>
> I re-ran the tapetype utility from our current AMANDA (version 2.6.1p2-3
> from Debian/Squeeze) and it showed this:
>
> define tapetype unknown-tapetype {
> comment "Created by amtapetype; compression disabled"
> length 1148746080 kbytes
> filemark 0 kbytes
> speed 69815 kps
> blocksize 32 kbytes
> }
>
>
> The length reported here is ~1.1TB which ties up with the "no space left
> on device" message, but ...
>
> ... these are genuine LTO-5 (Tandberg brand) tapes - just like
> http://img.misco.eu/Resources/images/Modules/InformationBlocks/1210/TAN/TAN-2/202175-tandberg-LTO-5-tape-cartridge-small.jpg
> - and the second tapetype above was created using a previously-unused
> tape and they really are 1.5TB native!
>
> What's going on? Why am I not getting to use the full capacity??
>
A guess only.
I note the measured speed has dropped by 45%. Due to what I haven't a clue,
but maybe some hardware change or cables or ???
Perhaps your system's ability to feed the drive has dropped below the
minimum needed to keep the drive streaming. In that case, the drive
must "shoe-shine" and each restart costs a bit of tape.
Jon
--
Jon H. LaBadie [email protected]
11226 South Shore Rd. (703) 787-0688 (H)
Reston, VA 20190 (609) 477-8330 (C)
