Re: TAPEBLK / TAPESZ setting with AIX

John Lee wrote: > > Currently we are using the default 16kb for TAPEBLK. > > We have a 5 GB 8mm tape drive hooked up to a RS6000 590. > > I would like to know what everyone else has this set to and what is the > highest/safest possible setting for this > (given the configuration that we have)? You have to ask IBM what is the largest efficient block size. We used to use 1024K on our systems because we found we got the best capacity and performance with that size. Then DG said that the largest block size the their tape arrays supported was 256K, however the drivers could support 1024K blocks it just broke them up into 4 physical blocks for the tape array. HOWEVER, said they, they had just discovered a bug that would mean that if we used blocksizes > 256K and one tape from the RAID5 tape array set failed they array would NOT be able to rebuild the damaged tape and we would be working without a safety net if another tape went bad. So, YMMV and contact your vendor for the full story. Art S. Kagel