DLT and Ultrium Tape drives

[Celsius Metech AB]

Hi,

Does anyone know if DLT80 or Ultruim (LTO) drives are supported on H70 and E35 using 10.20

Regards /Peter

[Robert-Jan Goossens]

Hi Peter,

Take a look at following link.

http://www.hp.com/products1/storage/compatibility/index.html

King regards,

Robert-Jan.

[Brian M Rawlings]

Peter: the answer is NO.

The reason is that HP does not support any DLTs larger than DLT7000 on HP-PB SCSI cards, due to throughput and speed issues. This is enforced since the HP-PB "tape2" driver won't work with DLT8000 on up.

The "stape" HSC scsi driver can work with the DLT8 and above, but not "tape2".

The underlying reason behind the lack of support is that slower tapes don't use up all the bandwidth (7-10 MB/s) of an HP-PB bus. FWD theoretical maximum is 20MB/s, but SCSI implementations vary on how much they actually can push across the cable, and HP-PB is too slow to run the bus at full speed.

DLT7000 runs at 5MB/s native, so even that one is problematic if you get 2:1 compression, and the drive wants 10MB/s. Your drive will probably run out of data from time to time, and have to stop (slowly, to avoid stretching the tape), rewind a little, then slowly start up to speed again to once again write data.

This is a well known issue with all streaming-type cartridge drives, if you can't keep data flowing to them fast enough -- the time lost doing the back and forth bit can double or quadruple the length of a backup, and prematurely wear out tapes and drives (1000 miles of motion for a 10 mile backup).

Now consider that DLT8000 is 6MB/s native (12MB/s if 2:1 compression), and you can see that the issue above is much more likely. Premature tape and drive failure are likely, instead of rare. Bad for HP, bad for you and your data.

Even worse, Ultrium 215s are 7.5MB/s, and Ultrium 230s require 15MB/s native to keep them streaming. Frankly, this is unlikely for even the fastest FWD (20MB/s max) bus adapters, which max out around 15-16 MB/s. And with any compression, FWD is just out of the question, you need UltraSCSI (40/80/160 MB/s) to keep their voracious appetites satisfied.

Likewise, SuperDLT is 11MB/s (sdlt 220) and 16MB/s (sdlt 320). Again, ultraSCSI is the only way to keep these big drives from wearing themselves out with all the extra start/stop motions.

So, that's the answer, and the basic reasons. Hope I didn't go on too long about it all.

Regards, --bmr

[Vincent Farrugia]

Hello,

Also worth mentioning... Although there exist some HVD DLT8000 drives, no such HVD Ultrium drives exist to my knowledge.

Bottom line is... you cannot. They won't even work well with a DDS4, let alone DLTs and Ultriums.

HTH,
Vince

[Leif Halvarsson_2]

Hi

HP Ultrium drives has a feature called ATS (Adaptive Tape Speed). If the host can't send data fast enough to stream the drive at full speed the drive can slow down to match the data rate. This means you neccesary not need the full 30MB/s to use a HP Ultrium drive.

http://www.hp.com/products1/storage/products/tapebackup/ultrium_tapedrives/ultrium230/infolibrary/whitepapers/ultrium_wp.pdf