Tape drives

Tape drive and auto-loader redirector over iSCSI

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gstephenson
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Tue Feb 22, 2011 10:12 pm

Maybe a silly question but if I have a two-node HA cluster, is it advisable to have an external tape drive connected to each node or would just one be enough?

Thanks,
Graham
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anton (staff)
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Tue Feb 22, 2011 10:15 pm

What do you want to do with this tape drive? Backup? Share? Please clarify. Thanks!
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Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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gstephenson
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Wed Feb 23, 2011 12:10 am

anton (staff) wrote:What do you want to do with this tape drive? Backup? Share? Please clarify. Thanks!
Backup as much of the nodes as possible including the files that comprise the SAN (.img), or perhaps even the entire node itself with the host partition. So backups only, no sharing.

Thanks.
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Max (staff)
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Wed Feb 23, 2011 9:49 am

We do not recommend to perform backups from the SAN side with the current version. Better idea is to perform client-side backups of the iSCSI drives. If you want to backup your SAN - just backup the starwind.cfg from the StarWind installation folder.
You can also wait for 6.0 - the feature you're looking for will be built-in so there will be no need to go for multiple software products.
Max Kolomyeytsev
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gstephenson
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Mon Feb 28, 2011 3:31 pm

Max (staff) wrote:We do not recommend to perform backups from the SAN side with the current version. Better idea is to perform client-side backups of the iSCSI drives. If you want to backup your SAN - just backup the starwind.cfg from the StarWind installation folder.
You can also wait for 6.0 - the feature you're looking for will be built-in so there will be no need to go for multiple software products.
Ok, so then if this is a HA cluster, is it safe enough to have a tape drive connected to just one node for taking client backups? Would the node with the tape drive be able to see all the files in the cluster even if it isn't the owner? I will be running vm's on both nodes and want to back them up using ArcServe. ...I guess then another question is: If I have to backup over a crossover connection, I can't use the synchronization link can I? I would have to have another crossover for this purpose?

When is v6 expected?
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anton (staff)
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Mon Feb 28, 2011 6:12 pm

You cannot share tape drive in this way. To say truth I don't know any single software doing clustered tape drive. Consider re-working your backup scenario. Say backup to disk (and it's HA cluster) and run background backup to tape. Tape backup CAN fail. Backup to disk - cannot (as it's HA-ed). If tape drive fails - re-run backup. You don't care about backup window as process runs in the background. Everybody is happy.
gstephenson wrote:
Max (staff) wrote:We do not recommend to perform backups from the SAN side with the current version. Better idea is to perform client-side backups of the iSCSI drives. If you want to backup your SAN - just backup the starwind.cfg from the StarWind installation folder.
You can also wait for 6.0 - the feature you're looking for will be built-in so there will be no need to go for multiple software products.
Ok, so then if this is a HA cluster, is it safe enough to have a tape drive connected to just one node for taking client backups? Would the node with the tape drive be able to see all the files in the cluster even if it isn't the owner? I will be running vm's on both nodes and want to back them up using ArcServe. ...I guess then another question is: If I have to backup over a crossover connection, I can't use the synchronization link can I? I would have to have another crossover for this purpose?

When is v6 expected?
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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gstephenson
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Mon Feb 28, 2011 6:43 pm

anton (staff) wrote:You cannot share tape drive in this way. To say truth I don't know any single software doing clustered tape drive. Consider re-working your backup scenario. Say backup to disk (and it's HA cluster) and run background backup to tape. Tape backup CAN fail. Backup to disk - cannot (as it's HA-ed). If tape drive fails - re-run backup. You don't care about backup window as process runs in the background. Everybody is happy.
Ok, so to clarify then, since it is HA using CSV, both nodes can see all vm's from either node, right? If node A has the tape, I can still back up a vm which is owned by node B since it is HA and then as you suggested I then back it up to another disk folder and from there to the tape? No need to use the network directly other than what the HA sync is already doing.

Sorry for my newbie questions. :o)
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anton (staff)
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Mon Feb 28, 2011 6:46 pm

It's true, BUT... You need some mechanism to lock/unlock the tape drive. For hard disks there's SCSI-2/3 reservation mechanism. For tape drive I doubt firmware supports any...
gstephenson wrote:
anton (staff) wrote:You cannot share tape drive in this way. To say truth I don't know any single software doing clustered tape drive. Consider re-working your backup scenario. Say backup to disk (and it's HA cluster) and run background backup to tape. Tape backup CAN fail. Backup to disk - cannot (as it's HA-ed). If tape drive fails - re-run backup. You don't care about backup window as process runs in the background. Everybody is happy.
Ok, so to clarify then, since it is HA using CSV, both nodes can see all vm's from either node, right? If node A has the tape, I can still back up a vm which is owned by node B since it is HA and then as you suggested I then back it up to another disk folder and from there to the tape? No need to use the network directly other than what the HA sync is already doing.

Sorry for my newbie questions. :o)
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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gstephenson
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Mon Feb 28, 2011 7:43 pm

[quote="anton (staff)"]It's true, BUT... You need some mechanism to lock/unlock the tape drive. For hard disks there's SCSI-2/3 reservation mechanism. For tape drive I doubt firmware supports any...

The tape is connected physically only to node A. I just want to make sure that node A can see the backup files that node B created in the HA SAN. So only node A needs a tape drive because it can see the backup files created by both nodes, just like a shared folder. Is that correct? ....If not, each node should have its own tape drive.
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anton (staff)
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Mon Feb 28, 2011 7:56 pm

No you cannot do it. Neither with StarWind nor with anything on Earth. Tape drives cannot be shared in the way say hard disk can be. Reservation mechanism for tapes is not implemented.
gstephenson wrote:
anton (staff) wrote:It's true, BUT... You need some mechanism to lock/unlock the tape drive. For hard disks there's SCSI-2/3 reservation mechanism. For tape drive I doubt firmware supports any...

The tape is connected physically only to node A. I just want to make sure that node A can see the backup files that node B created in the HA SAN. So only node A needs a tape drive because it can see the backup files created by both nodes, just like a shared folder. Is that correct? ....If not, each node should have its own tape drive.
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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gstephenson
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Mon Feb 28, 2011 8:54 pm

anton (staff) wrote:No you cannot do it. Neither with StarWind nor with anything on Earth. Tape drives cannot be shared in the way say hard disk can be. Reservation mechanism for tapes is not implemented.
Ok, so then I should be ok if both nodes have their own tape drive, correct?
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anton (staff)
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Mon Feb 28, 2011 9:05 pm

It does not sound like a great ROI plan to me. Read again what I wrote above: re-think your backup plan. Consider sliding away from pure Disk-To-Tape and use Disk-To-Disk-To-Tape instead.
gstephenson wrote:
anton (staff) wrote:No you cannot do it. Neither with StarWind nor with anything on Earth. Tape drives cannot be shared in the way say hard disk can be. Reservation mechanism for tapes is not implemented.
Ok, so then I should be ok if both nodes have their own tape drive, correct?
Regards,
Anton Kolomyeytsev

Chief Technology Officer & Chief Architect, StarWind Software

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