frecover fails with Ultrium tape drive

[Larry Rogers_1]

I changed the following settings in the fbackup configuration file(as recomended on page 30 of the HP white paper, "How to optimize the performance of hp ultrium tape drives").

Blocksperrecord = 128
Checkpointfrequency = 128
Readerprocess = 4
Filespersm = 300

Fbackup seemed to perform fine but when I tried to frecover I got:

frecover(2114) read error from input device (I/O error)
and unable to resync backup media.

I found the following workaround in hp document id: U0250623. I changed:

"-f /dev/rmt/0m" to
"-f hostname:/dev/rmt/0m"

This disabled the fast search feature and I was able to get my files back but the recover was slow.

My question is:
What are the optimal settings for fbackup/frecover when using a Ultrium LTO tape drive SCSI attached to a L2000 running HPUX 11.0

[Steve Steel]

Hi


points to check on Ultrium

Chip rev Selway CC needed for fbackup/frecover to work correctly .

/etc/sam/br/fbackup_config
blocksperrecord 128
checkpointfreq 128
readerprocesses 4
filesperfsm up to 500 ( start with 300 )

So that looks good

Make sure you have these patches

PHCO_23651 fsck_vxfs(1M) cumulative patch
PHCO_25424 cumulative fbackup(1M)/frecover(1M) patch
PHCO_25902 cumulative SAM/ObAM patch
PHCO_26017 user/group(add/mod/del)(1M) cumulative patch
PHCO_26111 libc cumulative header file patch
PHCO_27608 libc cumulative patch
PHKL_18543 PM/VM/UFS/async/scsi/io/DMAPI/JFS/perf patch
PHKL_20016 2nd CPU not recognized in G70/H70/I70
PHKL_22677 fix of getdirentries, MVFS, rcp, mmap & IDS
PHKL_24027 VxFS 3.1 cumulative patch
PHKL_24187 ioscan performance gain for SCSI Subsystem
PHKL_27003 SCSI IO Subsystem Cumulative Patch
PHKL_27303 SCSI Tape (stape) cumulative
PHKL_27364 Probe,IDDS,PM,VM,PA-8700,AIO,T600,FS,Hang
PHKL_27510 vfs cumulative patch




It is possible that your workaround is the solution for this drive


You could experiment with dd

dd if=/dev/rmt/0m ibs=10k | frecover -x -i/dir


Steve Steel

[Steve Steel]

Hi

I found some more on this

So it seems that you can make fbackup slightly faster by leaving all
the config parameters to their default and only change the config
parameter blocksperrecords, setting blocksperroecord between 16 and 64
would speedup the fbackup process , however going higher then 64 would
slowdown fbackup again.



steve Steel