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mlenny

Compatibility problems with Dell PowerVault 122T LTO Loader

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Okay, first the spec...

 

Dell PowerEdge 2500 with Adaptec 39160 card.

Dell PowerVault 120T attached to one channel, Dell PowerVault 122T attached to the second channel.

Running Windows 2000 Server SP3, Retrospect Multi Server 6.5.336, RDU 4.6.106.

 

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Now the problem...

 

There are times when Retrospect refuses to update the names of tapes in the 122T library, despite having scanned all media.

 

E.g. For last night's backup, I have "1-Daily Backup A" in slot 1. This morning, I export the tape from the slot and import "1-Daily Backup B" into the same slot for tonight's backup.

 

Retrospect scans all media, and when in the drive, reads the tape's name correctly. But when Retrospect ejects the tape from the drive, and returns it to the library, the tape's name still reads as "1-Daily Backup A" - the name of the tape that previously existed in that slot.

 

If I load the tape again and eject it, it may stick this time. I may have to do this a few times to get this to happen. If I clear the library slots information (shift-Scan Media) and try again, it may work, but then again, maybe not.

 

I am using ASPI for communication as the performance is around 800-850MB/min, as compared to the NT Passthrough's 450-500MB/min.

 

Any chance of a fix out there?

 

The PowerVault 120T behaves fine, but then the library function on that drive is a much simpler affair.

 

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Oh, and another related matter...

 

Whenever I need to swap tapes out of the library, I have to use the control panel on the 122T drive. As soon as I access it, the library disappears from Retrospect. Once I have finished on the control panel and returned the 122T to a ready state, I have to go to the Environment tab and rescan the bus to get it to reappear.

 

However, sometimes it will reappear by itself and even start a media scan. This is not very often, but welcome when it does.

 

Is there any way it can be fixed so that the library is always re-mounted automatically without having to go through the Environment tab and bus scanning every time?

 

 

Many thanks, Matt.

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Still haven't found a solution to these problems. I note that the latest RDUs improve support for some Dell PowerVault drives (alas, not mine).

 

 

 

Dantz: any chance of trying to resolve the issues I have with the PowerVault 122T?

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Hi

 

First a few things to look into:

-Make sure the windows drivers for the tape drive an loader are disabled in the device manager.

-Check SCSI card settings. Try manually setting the transfer rate on the card to match the spec of the interface on the loader.

 

Retrospect has no way to track changes in the loader that occur when you use the front panel to change tapes. The only way to keep track of those changes is to rescan the contents of the loader. You can get around this by going to configure devices in Retrospect and using the options there to load/unload tapes.

 

Thanks

Nate

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The Windows drivers are disabled for both the drives and the autoloaders.

 

I'm not sure what you mean regarding the SCSI card transfer rate: I have no issue with the speed or performance of the SCSI connection (ASPI is a lot faster than NT Passthrough).

 

The reason I bought it up was in case there is a known issue regarding communication with the autoloader over ASPI that may cause the problems with old tape names sticking on the slots when the tapes are changed.

 

Also, would this have any bearing on getting the library slots to reappear in Retrospect once the drive is back on-line, without having to resort to a manual rescan of the bus?

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Hi

 

SCSI cards and SCSI devices auto-negotiate data transfer rates on boot. In some cases that negotiation doesn't go well and you end up with communication problems. Booting into the SCSI BIOS and setting the card to match the capabilities of your device is one way around this problem.

 

When SCSI communication is flaky, odd things like what you have described happen.

 

Just out of curiosity, run a test with NT passthrough instead. I know it is slower but do the same problems occur? You can force Retrospect to use NT passtrhough by typing CTRL + ALT + P + P at any screen in Retrospect and enabling it under the execution menu.

 

Thanks

Nate

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Not had a chance yet. I will get round to it at some point, but as it's not a critical problem (more of a nuisance), I don't expect to try anything within the next couple of weeks.

 

I'll post once I've tried.

 

Of course, if rward3182 wants to try first, perhaps he'll post his results.

 

The race is on to see who gets there first!

 

Thanks.

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Hi mlenny / Natew

 

As I said this one is driving me crazy. This our production backup server backing up 8 other servers. We have been using it for 6 months. It has never worked very well with retrospect (despite being on the hardware compatabillity list). Retropect has always had some diffeculty communicating with the drive ie. send an eject command and the app hangs. Once or twice it has lost track of tape locations but a re-inventory on the tape drive use to cure that.

 

Current Symtoms

 

1. Can't identify the tapes properly does not update when tape positions change.

2. Even when we manage to get to recognise the tapes we do a check media and it says the media is ready but then when backup starts it can't find the tapes.

 

What I have tried.

1. Diabling the windows drivers for tape dirve

2. Using NT pass through rather than ASPI

 

This next plan of attack is to hard code SCSI data transfer rates. Then if this fails go to Veritas which is pity.

 

Roger Ward

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Okay: by transfer rate, do you mean the maximum *native* data transfer rate of the autoloader (in this case, it's 15MB/s), or do you mean the SCSI connection ( i.e. Ultra160)?

 

As I'm not sure, anyone care to take a glance at the 122T's tech specs?

 

http://docs.euro.dell.com/docs/stor-sys/122t_LTO/en/122t_lto/specs.htm

 

Can anyone tell me what I should be setting the SCSI card to? Also, anyone also know what specifically I should be changing on an Adaptec 39160 dual-channel card? It'll save me having to dig through the documentation!

 

I'll hopefully be trying this tomorrow night. I'll report back with any successes.

 

Thanks.

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Mlenny

 

Yes I to would like an explantion of this I can't find a way of changing the rate it the SCSI bios.

 

It still think this is retrospect issue I suspect the device driver is not working correctly.

 

It is now working again but communication with tape device is "flacky".

 

Maybe natew could ask his colleagues to take a look!

 

Roger doh.gif

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Okay, tonight was the night (a week late, I know).

 

I've set the transfer rate to 80 for the IDs on which both the PowerVaults sit. As they're both Ultra-2 SCSI, the absolute maximum is 80MB/s anyway (and the devices' maximum is even lower).

 

Just seen the first backup run and the performance seems on a par to before, so no detrimental effect on raw performance at first glance.

 

However, the library slots still do not automatically reappear once the 122T is put back on-line (i.e. its menu system is exited on its front panel). I had to do a manual rescan in the Environment tab to get them back.

 

As they have appeared automatically on occasions in the past, I don't know whether this is still symptomatic of a fault with either the communication or the drivers.

 

-------------------------------------------------------------------

QUESTION: Should the normal behaviour be that the slots all appear once the PowerVault is back online? It'd be good if this could be the case: I know this happens with the PowerVault 120T we have (the less-fancy DLT1 autoloader).

-------------------------------------------------------------------

 

Overall, I'll see how it all goes. If I get a reoccurence of loader errors and misbehaving, I'll try going down to 40MB/s. Again, the real-world performance of the drives means this shouldn't have much of an impact (if not, any) on their performance.

 

If that still doesn't fix it, I'd say it's time to revisit the Retrospect drivers.

 

I'd really love those slots to come back by themselves without a manual rescan necessary (can that be looked at in a driver update if it isn't the case already?).

 

Anyway, I'll keep you all posted, but it may be a while before I have anything to report. Don't you just love those intermittent problems!!!

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Uh oh! Now maybe this is partly my fault. Here's what has happened this morning.

 

I noticed a log entry saying the catalog is out-of-sync on one of the tape sets that run on the 122T LTO.

 

I go to the server and load up the 3 tapes that make up this set into the 122T. Of course, when exiting the 122T menu system, the slots do not reappear.

 

So I go to the Environment tab and rescan the bus... however...

 

At the time a proactive backup was taking place on the 120T DLT1 on the other SCSI channel of the 39160 card. This promptly failed with communication errors, and the 122T failed during its Scan Media (an error code 90) as it tried to load the 3rd tape in the loader.

 

The 120T sorts itself out eventually without intervention. I power-cycle the 122T and it also sorts itself out.

 

I do another Scan Media on the 122T and it reads back all the names correctly, but tapes 1 & 2 fail to get their names to stick once back in the loader. Although marked as verified (blue tape symbol), they have no names against them.

 

I manually drag each one into the 122T drive and once ejected again, all is well with their names appearing alongside their slot in the loader.

 

So, in summary, in one morning I experienced almost every example of misbehaving I had seen before. I must note that I don't usually access the drives whilst another backup is happening, so that particular fact isn't a common factor from my past experiences with these problems.

 

So it looks like I still have problems.

 

Any comments/suggestions?

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Hi

 

The next step is to make sure we have ruled out all the basics covered in this article. We won't be able to pursue this as a Retrospect driver problem until we have verified that all of these fail.

 

http://www.dantz.com/en/support/kbase.dtml?id=26499

 

Have you tried moving or deleting your Retrospect preference files? They are located at:

C:/documents and settings/all users/application data/retrospect/config65.dat and config65.bak.

These files contain all of your scripts and settings too so you might want to keep them on hand in case the problems continue with new configs.

 

Thanks

Nate

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