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Compaq DAT 20/40

 
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Scott_186
Advisor

Compaq DAT 20/40

Hi everyone.. first time poster here..

Device: Compaq DAT 20/40 SDT-10000

I got the HP L&TT app and I've went through all the test and everything seems to check out ok.. Well, my whole purpose of downloading that app was to test the compression.. because like the 187 posts I read before typing this, I understand what the compression should be, and I know what it's not..

Problem: Inside the app I only have 5 choices.. Analysis, Connectivity, Media Validation, Read/Write, Self Test.. I look in the Scripts folder and I see the "Compression Test" file, but how come it doesn't show up inside the app??!?! arrrgg..
24 REPLIES 24
Tina Karasch
Valued Contributor

Re: Compaq DAT 20/40

What it should be .... depends on your System and it's SW and HW - setup and off course, your data....

The L&TT application has originally been written with the firmware of the HP Dat40's in mind; not the pre-merge compaq dat 20/40 and it's firmware (inclusion is being worked on) - this is why you can see all at this point compatible tests in the pull down menu - if you go from within L&TT via "options" to "scripts" and it does display the script; you should be able to run it providing the unit has the latest fw and the L&TT version is the latest too.
( www.hp.com/support/tapetools/ )

Besides that you can actually check out what kind of compression you do get, by checking the job-logs of most major backup sw programs.

more info about compression and performance....

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=lpg50244

http://www.hp.com/cgi-bin/cposupport/get_doc.pl?SNI=hpsurestor18545&LC=information_storage&Tfile=lpg50167

http://www.hp.com/cposupport/information_storage/support_doc/lpg50460.html
If U want to; let's get technical.... :P
Scott_186
Advisor

Re: Compaq DAT 20/40

Thanks for the reply, but I've already read all of those compression tips and ideas pages.. It's ridiculous, it takes 8 hours to backup 22 gig of data!! WTF! I've never seen something that slow.. Anyway, like you were saying about running a Script in the L&TT, I tryed that.. The script doesn't show up in there.. Whats weird is, the people here are saying the before the 4 servers were upgraded to 2000 from NT4, it backed up just fine..
Anymore ideas?
Marino Meloni_1
Honored Contributor

Re: Compaq DAT 20/40

Yes, another idea,
If this appear after migration to w2k,and if the server is using a Adaaptec HBA, update your SCSI drivers, the first released ones with W2K had some trouble with domain validation and some time the negotiate at 5 MB/S async mode.
another tes is following the 3 link suggested, and to use the tools described, they are very usefulls in order to troubleshoot this kind of issue
Dave Dewar
Trusted Contributor

Re: Compaq DAT 20/40

Hi Scott,

I would echo Marino's comments. If you are acheiving 22GB on a 20GB native tape, compression is working fine and your issue is preformance. The win2K original adaptec driver feature is a good candidate. As Marino says the set of performance tools HP provide on the links above are excellent at pinpointing where the issue might lie.

Cheers,

Dave Dewar.
Scott_186
Advisor

Re: Compaq DAT 20/40

thanks guys.. but I've updated the SCSI controller drivers already.. didn't help.. also, it's a 40gig tape.. It looks like ARCserve is running 10 sessions on one drive.. casuing the 3.5gig to become almost 20 gig.. that's not right!! is it?
Dave Dewar
Trusted Contributor

Re: Compaq DAT 20/40

Hi Scott,

If you do really have 10 identical Arcserve sessions backing up to the single tape drive then that would slug your performance as well and is obviously not right. I have no diea what type of system you are running on but this would result in a processor and disk load and could mean that the actual tape drive is not getting data as fast as it would like.
I am making the assumption that you only want to backup 3.5GB of data - one backup job. Check you Arcserve scheduling and backup options.
The tape you are using might be called a 40GB tape, but that refers to its capacity at 2:1 compression. The native capacity of a DDS4/DAT40 tape is 20GB.

Cheers,

Dave Dewar
Scott_186
Advisor

Re: Compaq DAT 20/40

Ok.. that makes sence..

So, who's the genious that's gonna tell me how to test my compression? I have the hp L&TT tools.. but I don't have a compression test and it doesn't appear under available scripts to run.. hhmmm
Dave Dewar
Trusted Contributor

Re: Compaq DAT 20/40

Hi Scott,

The final link that Tina posted goes to a performance trouble shooting guide.

http://www.hp.com/cposupport/information_storage/support_doc/lpg50460.html

There are also set of tools we have provided to allow you to debug performance issues using the guide. These are available under support/drivers. The explains how to use these tools.

try this link for the tools:

http://h20000.www2.hp.com/bizsupport/TechSupport/DriverDownload.jsp?pnameOID=18547&locale=en_US&taskId=135&prodTypeId=12169&prodSeriesId=81997&submit.y=6&submit.x=8&cc=us#Microsoft%20Windows%20Server%202003

These should work for the compaq dat40 drive you have as well, although I am not sure whether we have actually tested it :-).

One of the tools is called HPcreatedata. This allows you to create data files of different compression ratios. You can then use the other tools to send them to the drive and measure performance.

Read the performance troubleshooting guide and try the tools.

Cheers,

Dave Dewar.
Scott_186
Advisor

Re: Compaq DAT 20/40

Ok.. I tested everything.. It all checks out ok! The part that I was most concerned about was the Read/Write speed to the tape itself.. it came back at 6mb/s so that's alright.. Throug-put was good. Subsystem read was just fine.. I don't know what else to do.. I think I'm going to try and stop alot of service tonight to try the backup that way.. any suggestions about anything?