Re: Trouble reading Informix backup on DLT device.

In article <5ieb98$frj@mn5.swip.net>, Christer Widell <mg17224@mailbox.swipnet.se> writes >Trouble reading ontape backup on DLT tape ! >Compressed or uncompressed backup om DLT-tape ? > >System: SUN Sparccenter 3000, Solaris 2.5.1, Informix 7.20.UC2 > >We take an Informix backup via crontab command every night: > >Command in root's crontab: >00 05 * * 1-5 su - informix -c "ontape -s -L 0" > >After first delivery of new DLT-4000 tape device with supplied 5 tapes (DLT IV) >everything was OK. Writing backups and reading tapes worked OK. > >When we bought more tapes (another 10 now DLT IV with blue SUN logotype) from >SUN Express and put them into circulation everything seemed perfectly until >first attempt to read the backup tape. It was not readable!! The system did not >seem to like to read the tapes (error in the beginning of the tape). > >After some investigating by service engineer it seems that the system was >configured (Informix onconfig TAPEDEV) for compressed backup and the new tapes >could not handle the format. It seemed that writing backup worked OK but >reading worked not OK. > Informix does not support writing to compressed tape devices - probably for exactly this reason.... > >ONCONFIG ># System Archive Tape Device >TAPEDEV /dev/rmt/2c # Tape device path >TAPEBLK 126 # Tape block size (Kbytes) >TAPESIZE 40000000 # Maximum amount of data to put on tape >(Kbytes)> ># Log Archive Tape Device >LTAPEDEV /dev/rmt/1n # Log tape device path >LTAPEBLK 126 # Log tape block size (Kbytes) >LTAPESIZE 8000000 # Max amount of data to put on log tape >(Kbytes)> >After correcting to uncompressed format. >TAPEDEV /dev/rmt/2 # Tape device path>Everything seema OK, both writing and reading (at least the labels of the tape >with ontape-commands) > >Questions >Is there two (or more) "tape qualities"? (All seems to bee DLT IV tapes.) >Is there a special problem with "parameters etc." for using compressed or >uncompressed backups on DLT 4000 ? >We have plenty of space on DLT tape is uncompressed format the best ? > >Any suggestions or tips regarding this matter i most welcome. > >/Best regard Christer Widell cwidell@hotell.itz.se > -- David Williams