Re: Backup problem

machayach@okzim.gaia.co.zw wrote: > > In article <358530AD.43CC@bloomberg.net>, > kagel@bloomberg.net wrote: > > > > machayach@okzim.gaia.co.zw wrote: > > > [SNIP] > Is there any way I can change the block size parameter by increasing it so > that more data is written on a small block. Yes, however your tape drive and/or device drivers must support this. For example there was a bug in DG/UX whereby the driver would accept a blocksize of 1024, as you have here, but the tapes could not be read back after apparently having been written successfully. We had 4 months of useless backups! In addition while discussing this with DG technicians we discovered that the DLT drives we are using only actually support physical block sizes <= 256K. The device driver would allow larger logical block sizes and output multiple blocks. But, the only gain to larger blocks was additional buffering to keep the tape arrays streaming better but no gain in storage capacity. It was this code extended blocksize code that was broken. So we found we had to back down to 256K blocksize and have not changed it back since the drivers were fixed. So caviat emptor and YYMV! > > > MODIFYING TAPE PARAMETERS > > > > > > Tape Device [/dev/rmt/1m ] > > > > > > Block Size [ 1024] Kbytes Tape Size [ 4000000] Kbytes > > > > > > Log Tape Device [/dev/rmt/2m ] > > > > > > Block Size [ 1024] Kbytes Tape Size [ 4000000] Kbytes Art S. Kagel