Re: tape drive performing slow with star?

From: T.T. Harris (spamwontsurvive.this_at_iwont.get.it)
Date: 02/06/04 

Date: Fri, 6 Feb 2004 16:52:01 +0100

"Oscar del Rio" <delrio@mie.utoronto.ca> schreef in bericht
news:c00c7i$rb4$1@news.mie...
> T.T. Harris wrote:
> > We are using a Sun Fire 280R with an internal DDS4 tape drive on Solaris
8.
> > The system was backing up about 25 gig in documents and some
miscellaneous
> > other stuff to this tapedrive using ufsdump.
> >
> > The tape transfer rate was a "staggering" +/-3000 KBps.
> >
> > I figured that's too low, so we recently installed star.
>
> Aren't those tape drives rated at about 3 MB/s sustained, native
> transfer rate?
>
>
http://www.hp.com/products1/storage/products/tapebackup/dds_dat_drives/dds4_
dat40/infolibrary/surestore_dat_40_tape_drive.pdf
>

WOW... you're absolutely right... I've been looking around at Sun's website
for something just like that. I guess I should've known to look to HP when
using the mt status command :-/

Though it's still curious to see that I should be able to sustain about 6
MB/s, assuming /dev/rmt/0 defaults to compressed high-density.
Although I have no idea how to check this, logically speaking (since there's
about 25 gig moved to tape) this should be the case, since the tape will
only hold 20gig uncompressed.

Relevant Pages

  • SUMMARY: How to speed up LTO3 transfer ?
    ... after a few tests done with Casper Dik it turned out that ufsdump is the limiting factor; ... changing 'blocking factor' of ufsdump doesn't help ... DUMP: 91.76% done, finished in 0:35 ... ing factor available with most tape drives is 126. ...
    (SunManagers)
  • Re: Anyone used Solaris Secure Shell, Suns productized ssh for Solaris9?
    ... for ufsdump it does nothing. ... As thiswears out the tapes it even makes your backups ... Only if your tape medium is faster than your local CPU's ability to process ... > Create sub nets that are more secure and others that are less secure. ...
    (comp.security.ssh)
  • Re: (mirroring &) ZFS: 9=no-ZFS; 10=yes?; 11=open=ZFS (improved)?
    ... restores in that case? ... With 'ufsrestore -i', tagging the files or directories you need. ... a lot of tape to get what you want, but you don't need enough spare ... ufsrestore (and presumably also ufsdump) directly access the tape. ...
    (comp.unix.solaris)
  • ufsdump doesnt unload tape
    ... Some extra details: Scsi is via a SunSwift card, then a Dec SCSI SE to ... When I run ufsdump with the 'l' option (that's a small L, ... next tape, to continue the dump. ...
    (SunManagers)
  • Re: ufsdump very slow
    ... I have noticed for some time(after changing tape device) that the new ... ufsdump and that the disk that is beeing dumped is fully loadedbut ... Bottleneck here is how you are using ufsdump. ... drives are fast. ...
    (comp.unix.solaris)