Re: taper tunning to achieve tape streaming

[Mitch Collinsworth]

On Wed, 12 Dec 2001, Mihai Lozoveanu wrote:

 Does anyone know how to  modify the buffering ot the  taper so that I can achive
 tape streaming. I'm using an dlt8000 tape on an enterprise e250 sun server. When

Are you using a holding disk?  Or backing up direct to tape?

-Mitch

Re: taper tunning to achieve tape streaming

[Mihai Lozoveanu]

 Mitch == Mitch Collinsworth [EMAIL PROTECTED] writes:

Yes, I'am using 20G for holding  disk.  I had two files  produced by amdump each
one 9G.  The taper doesn't  achieve streaming when write  them to the tape  (and
the rate is around 4MB/s instead of 5.9MB/s which is nominal).  I tried to write
them manually with tar  on the tape (aside  from  amanda). Tar behaves the  same
unless I increase  the bloking factor to  128/256 when it reaches full streaming
and the rate gets to 5.6MB/s.

I  also tried to  increase  the number of  tapebufs  (more than  20) (altough  I
realized that it doesn't buffer the  communication between taper and tape device
drive) and  I   got an  error.   I believe   that it  comes from  shared  memory
allocation  that has reached  its per process limit (640K  - which  I think it's
enough).

Thanks for any help,
Mihai.


 Does anyone know how to  modify the buffering ot the  taper so that I can achive
 tape streaming. I'm using an dlt8000 tape on an enterprise e250 sun server. When

Mitch Are you using a holding disk?  Or backing up direct to tape?

Mitch -Mitch

taper tunning to achieve tape streaming

[Mihai Lozoveanu]

Hi,

Does anyone know how to  modify the buffering ot the  taper so that I can achive
tape streaming. I'm using an dlt8000 tape on an enterprise e250 sun server. When
write the same files to the tape  using tar with blocking factor  126 or 256 the
tape gets into full streaming.

The tapebufs parameter seems to  control the shared memory  buffers to taper and
not from taper to tape driver.

Thanks for any help/ideas,
Mihai.