SCSI adapters for 9000 D270/D280

[telemark pelle]

Hi,

Does anyone know if it's possible to find LVD scsi adapters to D270/D280 servers..?
I'm trying to connect an Ultrium-3 drive to these old machines.
If not, what would the appropriate part number be for a HVD controller for these machines?

-pelle

[Torsten.]

Hi,

because the controller cards are using the GSC bus, the number of controllers are very limited.
There are only HVD and SE SCSI controllers available.

The SE SCSI is compatible, but too slow.

I guess it will not work to connect a Ultrium-3 to this old server.

This tape drives are not available for HVD AFAIK.

[A. Clay Stephenson]

About the only thing that would have a prayer of working reasonably on one of these old beasts would be an A4107A HVD controller coupled to an HVD/LVD bus converter. Such a converter is made by paralan and Blackbox.

http://www.paralan.com/converters.html

http://www.blackbox.com/Catalog/Detail.aspx?cid=308,1559,1566&mid=3202

[Andrew Rutter]

hi,

The nearest to Single ended scsi available is the Eisa interface A2679A with a 50pin ext connector.

Only any good if your running 32bit kernel though, and it would be very slow, and not really recommended

A4107A is the FWD interface.

Andy

[telemark pelle]

Hello all three.

Thanks for your help.

-pelle

[Bill Hassell]

Before you waste your money on adapters and the Ultrium-3 tape drive, the D-class servers are far, far too slow to use the Ultrium tape drives. Ultrium tape drives are not just bigger tapes, they have enormous data throughput requirements. Unlike reel-to-reel tape drives from the last century, new drives (DDS, DLT, AIT, Ultrium, etc) are streamers. They do not start and stop instantly. Instead, they must slowly spin up and run at only one speed and density. Now the Ultrium drives are so fast (about 80+ Mbytes/second for the Ultrium 960) that they incorporate a data rate matching (DRM) feature which actually slows the tape to as little as 27 Mbytes/sec. But that is for uncompressible data. If your data can be compressed 2:1, then your machine must supply more than 55 Mbyte/sec to keep the drive from stopping, backing up and restarting.

On a good day, with no activity on the system, your D-class boxes can probably get data sequentially at 20 Mbytes/sec, still too slow for the Ultrium 960. Look at the Ultrium 215 or 230 which can run as slow as 6 Mbytes/sec which matches your system speed. These slower drives will run much faster (2x-4x) than the Ultrium 960 because they won't have to stop and restart all the time.

[telemark pelle]

Hi all.

Thanks again for the answers. I bought a hvd scsi card for a small amount of money, used a lvd/hvs scsi converter and the drives I tested, LTO-3 and LTO-1 seemed to work fine.

I'm trying to find a good way of testing the speed to see which one is the fastest of the 2 drives on this machine.

Regards
pelle

[Bill Hassell]

The simplest test for a tape drive is to backup a meaningful amount of data (more than a few megs), something that will take 5 or 10 minutes. That something might be /var or /usr. Now a simple tar will be the worst for performance. The records will be 10k and each write is followed by a disk read and then write to tape. Find out approximately how much data is used with the du -kxs command as in:

du -kxs /var

Then using the number of Kbytes returned from du, divide that by the number of seconds for a bytes/sec speed rating. Note that test #1 will be skewed because of buffer cache effects. Run it again for a more useful time. Then do the same for another drive.

To maximize performance, use fbackup for the tests along with the requisite config file:

blocksperrecord 4096
records 64
checkpointfreq 4096
readerprocesses 6
maxretries 5
retrylimit 5000000
maxvoluses 200
filesperfsm 2000

The fbackup command line would be something like:

fbackup -i /var -v -c config-file -f /dev/rmt/0m

Unlike tar (cpio, pax, ftio, dump, vxdump, etc), fbackup is a high performance program designed to keep high speed tape drives running at full speed.

For /var with 500 megs of occupied data, you can expect the LTO1 drive to run at 7.5 min to 30 Mbytes/second (HP Ultrium 230 is the fastest LTO1) and 60 to 120 Mbytes/sec for LTO3. If you are measuring siginificantly lower speeds, the computer + disk is too slow to support the LTO drives.

[telemark pelle]

Thanks again. I understood now that I have a lot to learn when it comes to Unix. Of course I used tar and even more of course my file system is now full so I'm trying to clean it up and I will try your hints/tips.
Thanks a lot.

-pelle

[Bill Hassell]

> my file system is now full ...

This will be very helpful:

du -kx /var | sort -rn | head

This shows the largest directories. Inside a directory, use:

ll | sort -rnk5 | head

If /var is OK and / is full (and it happened after you ran tar), you very likely misspelled the the device file name. /dev/rmt/om creates a very large file while /dev/rmt/0m will write to the tape -- assuming 0m is the tape drive.