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tcsabina
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backup speed with iscsi-passthrough

We have just virtualized a customer environment, inculding iscsi-passthrough for the backup tape unit. A virtual windows 2003 server using this device with ArcServer 15.

The data transfer speed is around 130MB/min (so backup ~70GB takes ~10+hours).

Could we gain more speed out from the system, or this is a limitation of the iscsi-passthrough thing?

I know that there are several factors involved in the speed, but I would like to know first is it a normal operating speed.

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idle-jam
Immortal
Immortal

what if you do a disk to disk to tape backup instead? sometimes the drive maybe too slow to accept the data.

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farkasharry
Hot Shot
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Are you using the Software ISCSI Adapter? If yes, and your NIC´s are offering ISCSI, use them.

It is faster as they are using the vSwitch only for Auth, but then traffic goes directly from kernel to the storage!

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tcsabina
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The disk itself has issues. The raid contorller battery is dead, so there is no write cache at this moment.

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tcsabina
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harryfarkas, sorry but I don`t understand what you mean. Let me explain what we did:

- put the scsi card in the ESXi host, and attahce the tape unit (external).

- the tape device was not reconginsed properly, so we used: http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=102615...

- after this we were able to add a new SCSI device to an existing Windows 2003 VM. And the server is able to use it with ArcServe.

We haven`t installed any additinal software on the VM, only ArcServe v.15.

The device is visible in Device Manager, but it looks like this:

? Other devices

   ? HP Ultrium 2-SCSI SCSI Sequential Device

Thanks for the replies!

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farkasharry
Hot Shot
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Do you mean that the disk is visible but not being recognized in the device manager of the OS? If yes, it might be a windows issue! Smiley Wink

Is the tape device recognized somewhere in the ESX storage adapter area?

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tcsabina
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The tape unit is visible in the Device Manager. Also the name of the device is there. Just there is a ? next to it.

And ArcServe is able to use the device. The only thing is this 130MB/min speed.

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farkasharry
Hot Shot
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What about trying to import it in windows?

Von: tcsabina

Gesendet: Freitag, 18. März 2011 13:18

An: Harry Farkas

Betreff: New message: "backup speed with iscsi-passthrough"

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backup speed with iscsi-passthrough

reply from tcsabina<http://communities.vmware.com/people/tcsabina> in VMware ESXi™ 4 - View the full discussion<http://communities.vmware.com/message/1719472#1719472

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tcsabina
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Sorry, but I don`t get what do you mean. What do you mean with importing?

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farkasharry
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Do you have the latest driver from HP for the device?

What about this: http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1053276 

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tcsabina
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Haven`t installed anything on the Windows VM for this device. Only the backup application.

Will give it a try.

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farkasharry
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Did the correct HP driver help to sort out this issue and answer your question?

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tcsabina
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Sorry not to reply earlier.

I`ve installed HP Tape Library tools. The device is now properly identified in the device manager.

Did firmware updates, inistalled latest drivers, run every available test that are in the library tools.

But the devices still operates at 130MB/min...

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farkasharry
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If my answer was even partially helpful, please rate it! Thank you!

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DSTAVERT
Immortal
Immortal

VMware only supports parallel SCSI tape and loaders attached to an Adaptec parallel SCSI card. http://kb.vmware.com/kb/1016407 You have mentioned RAID card earlier in your post and most tape devices don't do well connected to a RAID card. Unless this card has external ports specifically for attaching tape devices I would try another card. You also mentioned the battery being dead. Do you have that corrected? I would pull the card and set it up in a physical machine and test to verify the functionality of the drive, software etc. I would also be inclined to leave the tape device attached to a physical machine even a workstation. 

-- David -- VMware Communities Moderator
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tcsabina
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The tape unit is external. I do understand what you say, that most raid cards are not good for tape units. But just the mention, this is an external tape unit, attached with an cable to the external port of the raid card.

Another thing that this tape unit and the raid card was previously working fine in another server, running NetWare (phisical). There were no issues with speed.

So 2 things can be:

- iscs passthrough

- the dead raid battery (no, it hasn`t been solved yet)

Thanks for the comments, and for thinking with us!

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DSTAVERT
Immortal
Immortal

Check to see that the external ports on the RAID card are specifically for attaching tape. Not all are. The only supported attachment is to an ADAPTEC SCSI card. What model of Adapetc card do you have? I would also make sure to get the battery situation taken care of.

Check your log files for potential problems. Both the Windows Event logs and the VMware logs will be helpful. Look for SCSI resets, disconnects etc. You can use the ESXi realtime log window (ALT + F12) to watch as the tape drive is being accessed. I would perhaps do a search through the forums for any mention of your tape drive model to see if anyone else has had similar issues and possible solutions.

I would seriously consider just attaching the tape to a physical machine. Just because you can virtualize things doesn't mean that you need to virtualize everything.

-- David -- VMware Communities Moderator
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tcsabina
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The card is an LSI53C1030. The tape is an Ultrium-2 drive from HP. This setup was working fine in a `physical` setup for years, so I think the card+tape drive is good/healthy. On this physical server we were using ArcServe on Netware as a software solution. We stuck to ArcServe, but now on Windows. But I don`t think so that could be and issue.

How can I check the realtime log window remotely of the ESXi host? I have ssh access to the server, and have the vSphare client.

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