msl6030 e1200

[JJ Urich]

I recently upgraded my backup server (zx6000) to 11.31. I have a MSL6030 with two 960 drives connected through a 2Gb/s HBA to an HP 2/8 switch, which is also running at 2Gb/s. Firmware for the msl, ultrium and e1200 are all at the latest versions and I'm running LTT version 4.5.1.0.

My problem is that I'm not seeing good performance #'s when I test a single drive with LTT. See below:
# blocksize 128k or 131072, reps=32768, block count=8, random (not compressible)
- Device Performance Test Started on Drive (Ultrium 3-SCSI) (3.0.2[1-6/0/2/1/0.1.7.255.0.0.2])
- Opening Tape Drive 3.0.2[1-6/0/2/1/0.1.7.255.0.0.2]
- Successfully opened the Tape Drive /dev/rmt/1mnb
- 4294 MB written in 37.6068 seconds at 114.2072 MB/s
# blocksize 128k, reps=32768, block count=8, 2:1 compression
- Device Performance Test Started on Drive (Ultrium 3-SCSI) (3.0.2[1-6/0/2/1/0.1.7.255.0.0.2])
- Opening Tape Drive 3.0.2[1-6/0/2/1/0.1.7.255.0.0.2]
- Successfully opened the Tape Drive /dev/rmt/1mnb
- 4294 MB written in 37.6078 seconds at 114.2042 MB/s
# blocksize 128k, reps=32768, block count=8, 4.3:1 compression
- Device Performance Test Started on Drive (Ultrium 3-SCSI) (3.0.2[1-6/0/2/1/0.1.7.255.0.0.2])
- Opening Tape Drive 3.0.2[1-6/0/2/1/0.1.7.255.0.0.2]
- Successfully opened the Tape Drive /dev/rmt/1mnb

[JJ Urich]

I would think that I should get closer to 160Mb/s with the 2:1 or 4.3:1 compression tests. Any one having issues with 11.31 and performance or am I missing some thing more basic?

Regards,

JJ

[Gergely Gardonyi]

Did you have an replies? I have similar issues. MSL 6030 with 1840 drive, 4GB fibre and I'm getting around max 120MB/s using LTT. I suspect the E1200 is the bottleneck but couldn't confirm it yet.

[JJ Urich]

No replies. I have the tape drives presented via FC to a rx2620 with 11.23 and got the same slowish results, so it isn't OS dependent and I suspect is a limitation of the e1200.

They have a newer 4G e2400 (i think) card out but I haven't ordered it yet as it is rather pricey.

Only test left is to direct connect drives via scsi, but I don't have any ultra320 scsi cards so haven't been able to test that case.

Regards,

JJ

[GustavoT]

If you have the E1200-160 (2GB) NSR with LTO 3 tape drives there's a big chance of limiting the performance of the drives. For those tape drives it'll be better to have a E1200-320 (Product Number AD577A)with a Ultra 320 bus. E2400 is not supported on MSL6000 Tape libraries.

As for the LTO4 tapes drives, it is recommended to connect the tape drives to separate NSRs since these drives are very fast. You can find more information here:

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&objectID=c01122518&jumpid=reg_R1002_USEN

[JJ Urich]

Right, it was the e1200-320 I was remembering, not the e2400. I do have the e1200-160 as I think that was all that was available and/or recommended by HP 3 years ago when I bought the library.

The e1200-320 says it is capable of 230MB/s max throughput, so i guess we shouldn't be too surprised that an e1200-160 max outs around 120Mb/s.

I have to laugh when so many peers talk about the death of tape because it is to slow when the majority of time people don't even realize their disks can't keep up with the drives they have today, let alone the new faster ones they won't buy because they aren't "fast enough". Sigh.

Cheers,

JJ

[Tom O'Toole]

JJ - do you know what doc. specifies the 230MB/s bandwidth on the e1200-320? I'm getting 215MB/S writing to two LTO4 drives at once with that device, so that sounds about right (using a 64K block size). I get 135MB/s writing to a single LTO4, and I don't know what the bottleneck is there.

I think the numbers you are getting - 115MB/s - are pretty good for LTO3, maybe a little too good for non-compressible data, native data rate is supposed to be like 80MB/s!

Are you saying your numbers got worse after your OS upgrade?


Yeah, it's funny hearing marketeers of DISK-TO-DISK-BACKUP, etc.... denegrate tape... Meanwhile we're complaining about ONLY getting 115MB/s (or 135MB/s, with 256 bit encryption)... I'll stick with tape, where it's appropriate, thanks....:-)

[JJ Urich]

The doc was the pricing guide for our University contract found below:

http://gem.compaq.com/gemstore/ctobases.asp?ProductLineId=1&SubFamilyId=1174&familyID=1154&oi=E9CED&nTab=1&DisplayType=Y&BuyIt=N

It is undoubtedly spelled out in the N1200-320 manual some where as well.

No, I wasn't implying it was slower after going to 11.31, just listing the OS I was running. 11.23 is the same speed.

This thread was primarily in reference to the fact that when using LTT to verify my setup, I wasn't scaling as I bumped up the compression. You'll see my number for 2:1 compression yieled 114 mb/s and going to a write test with 4.3:1 compression yielded the same speed, so that is the issue and the e1200-160 is the bottleneck.

JJ

[Gergely Gardonyi]

I found this. We get around 160MB/s with one LTO4 drive.

http://www11.itrc.hp.com/service/cki/docDisplay.do?docLocale=en&docId=emr_na-c01122518-4

[Tom O'Toole]

Gergely - Can you post the details of your platform where you are getting 160Mb/s through the NSR? I would be pretty happy with that number. What OS, application, and blocksize are you using, and how do you have the number of buffers set on the e1200-320? And anything else special you can think of - THANKS!