Dat24i

[CA1109109]

I am using Dat24i C1555A in LH2 Netservers running Arcserve 6.6 for Netware. The OS is NW4.11 so L&TT can not be used. (We will be upgrading within the next 6 months hopefully) I am getting a an error message from the Alert module that the tape drive is having a problem writing to the tape. E6924 Warning & E6932 Critical. Using TapeAssure the drive shows up as a C1537A. I have run all the diagnostics and it Passes but does not give me a throughput figure. The firmware version is L812. I wanted to update the firmware but L111 is the only version that I can find (with great difficulty I might add)from the HP Support Site. Is this a later version than the firmware currently installed on the drive? Also it would be helpful if anyone can give me an idea on how to improve the throughput. It is writing @ 12,000KB/Min or less. I've seen other DAT24's write at much higher speeds. Tapes are new.

[meloni]

here is how to upgrade the firmware with dos via floppy disk
http://h20015.www2.hp.com/hub_search/document.jhtml?lc=en&docName=lpg50251

[BR702707]

Similar set up her on NW3.2 and an LC3.

Check out http://support.ca.com/techbases/as61/10015.html For me the fix was to increase the Directory Cache Buffers - took backups form 10 hours down to 3!

[CA1109109]

Thanks for those Responses. Do you know if
the L111 firmware version is the latest. As I said the version in my tape drive is L812.

[meloni · Accepted solution]

Yes L111 is the last Fw version for surestore DAT 24

[CA1109109]

Hi - Back Again,

Well I sucessfully upgraded the Firmware to L111. No change in throughput. I changed the SCSI drivers to the .Ham from the .DSK Drivers and made the appropriate CDM loads in Arcserve6.6. Still No change in throughput. As suggested in an ArcServe Support Doc. While in a backup, disable tapeserver writes which forces the Program to write to a bit bucket. Through put went up to +40,000KB/min. This isolates the problem to the SCSI Channel, the tape device or the Media. Next, as a test I switched from using DDS3(125M)tapes to DDS(90M)tapes. I backed up about 1GIG of info and throughput went to 39,000 KB/min. So I believe, that test eliminated the SCSI Channel as the prob. I opened a brand new DDS3(125M)tape. Ran the same backup job with the DDS3 tape and throughput goes back to around 12 to 14,000KB/min. According to HP Documentation the DAT24 (C1555A) Tape drive is compatible with the DDS3 tape format. Am I missing something here??? Anyone know what I need to do next??? Is there some sort of calibrtaion needed? Are there any tools other than L&TT to calibrate HP Tape Drives?

[CA843380]

Hi,

The C1537A DAT24 and is compatible with the DDS3 tape format. Maximum native throughput with DDS3 tapes is 1MB/sec, 60MB/min. Data that is 2:1 compressible will result in double this tranfer rate.
When you put in your 90m tape you were running the DAT24 in DDS1 mode (or DDS2 mode with a 120m tape) you will have a native transfer rate of 510KB/sec, 30MB/min in this mode.
So when you got 38MB/min in DDS1 mode you have some compresion occurring.
With the same dataset you should get about 75MB/min when you use a DDS 3 tape in your drive.

You are obviously not getting this performance.

The test you ran with Arcserve6.6 does suggest that your maximum is around 40MB/min and yet the drive should be capable of 60MB/min native in DDS3 mode.

It is possible that your drive would fine fine in DDS1 and DDS2 mode but could struggle in DDS3 mode, however, I am surprised that the reduction from 40 to 12-14 is so large and I wonder whether there is some buffering issue with the OS and Arcserve that only manifests itself when the tape drive wants to go much faster than the OS/arcserve can do.

You mention that you ran tapassure and it gave the drive a "clean bill of health". Did you use a DDS3 tape during these tests?

Do you have any DDS2 (120m) tapes that you could try. You should get the same performance at your 90m tape. If you don't it could indicate a drive issue.

Do you have the ability to run the tape drive on a windows system to use LTT? I realsie this might be a hassle for you but this would really allow us ot check out you drive using the support ticket you could generate.

I am not aware of any diagnostic tools apart from tapeassure that work on Newtware4.X

There is a tool written by Novell called DPMETERM that writes to tape from memory to isolate disk/filesystem issues but I think this is only supported on newtware 5.1 upwards.

We do have a performance troubleshooting guide at the following link that might be of some use
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=lpg50460&locale=en_US#N10A0D

Cheers,

Dave Dewar

[Moe Howard_1]

I think if you remove the rostrum and give it an alcohol bath. Also doing that in addition to putting electrical grease to the spindle will increase the data transfer rate to maximus tranfer rate. After all that you can stick your head in a 5 gallon spackle bucket with pair of speedo's on. Then pack mayo on your taint. How about buying a new tape drive you looney.