Re: Compression-enabled tape archiving
At 01:29 PM 10/14/96 GMT, sdean@mhv.net wrote: >We have had a very messy last week or so at our AIX-Informix shop: >our month-old not-so-highly-available EMC Symmetrix RAID box had a messy >single-point of-failure outage....which sprinkled garbage all through its mngmnt >system...the hardware was fixed in an hour, but the Informix (V5 running o >AIX 3250) DB has been burping ever since. >ANYWAY, We use 8mm tape drives for our archives and logging....these are >the standard IBM or Exabyte 5 (uncompressed)-10 (standard, nonexotic, done-in >the-Exabyte-hardware compressed) or 7-14GB drives. >Informix is telling us that they only support uncompressed archiving. This to me >is insane. since compressing the data stream before archinving it makes the archive >run twice as fast....4-5 hours instead of 8-10.....The deity above only knows how >a restore would take uncompressed, but my guesstimate is 12-16 hours....and, given >the near 100% upti;me demaded by today's business climate, a restore that takes >that long is about as useful as a lead life-preserver. > >Has anyone done restores from compressed 8mm tapes? Comments, suggestions?? > I agree with you, Informix's policy re: the use of H/W compression, is ridiculous!! In any event, I've been using exabyte 8505's for some time now, both with compression, and without. I have used compression on our production systems, and it does facilitate a faster backup (like you, I've seen backup times cut inhalf). I have also successfully restored from these tapes (all 10 of them) on more then one occasion (fortuneately more attempts have not been necessary). CAUTION: At one point, Exabyte had a bug in their compression algorythm, which was discovered with Informix. Something about a specific bit pattern which caused problems. The current 8505's should have the new firmware, but best to check with your vendor to be sure. Jon -------------------------------------- Jon C. Vemo jvemo@cyberspace.com Bothell, WA USA --------------------------------------