Best way of connecting iSCSI volumes to server?

Soldato
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The hardware:
Nimble CS215 w/10GbE iSCSI
3 x vSphere 6 host servers

Software:
File server - 2012R2 with deduplication enabled
Arcserve UDP and Arcserve backup r16.5

Currently my iSCSI volumes on the Nimble are presented to a vm via in guest iSCSI initiator. Backups run daily to Arcserve UDP for the VMs, and they run every friday (finishing on early sunday morning) to tape for the data from the file server.

When the backups run on the weekend to tape and the deduplication tasks (garbage collection etc.) run on the weekend my dedupe savings go all over the place on the nimble.
It has been suggested that in guest iSCSI might not be the way to go here (Old fashioned way of doing it apparently) I know my alternatives are RDMs or VMDK but I'm not sure of the pros and cons of each in relation to the way i connect currently. Any suggestions on making my dedupe setup more reliable?
 
Soldato
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How much data do you have? Do you have VCenter server or are your hosts standalone? Is the Nimble standalone or are you replicating?

Where are you storing your VM boot disks at the moment? I presume not on the Nimble if you're using in guest iSCSI.

Unless there is something special about your environment presenting LUN's off the Nimble to VMWare as VMFS datastores and using VMDK's is the usual way to go. If you need to present a LUN directly to a guest use a virtual RDM. Physical RDM's have a lot of limitations and there are limited use cases for them these days.

I'm not familiar with ArcServe, but if your environment is mostly virtualized Veeam is hard to beat for backups. It will read the VMDK's directly and gives you a lot of flexibility. It's not cheap, but it is good value IMO.
 
Soldato
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2.6TB, 2TB and 1.6TB are the 3 volumes i have allocated within the VM using in guest iscsi. With 2.1 used, 1.6 used and 800gb used.

We do have a vCenter server and 5 hosts and the Nimble is standalone.

The VM boot disks are all on the Nimble, the reason for the in guest iSCSI on this one virtual machine is purely from the basis of having been setup that way years ago with the last storage unit + server 2008R2. I'm a bit of a jack of all trades, one day i work on SCCM the next I'm off into a switch cupboard, so lots of gaps in knowledge...this being one of them.

I knew it wasn't possible to do VMDKs with disks this big prior to ESX5, but I'm not really sure of the implications each configuring will have on the way I'm using it and the size of the data.

Arcserve UDP is essentially veeam but cheaper. It often gets a bad reaction because of the Arcserve name, but it's absolutely brilliant....i was actually the first customer to install it in the UK when it was released 2 years ago! :D

What sort of time scale would i be looking at to convert this much data to a VMDK? I know how to do it, but while it converts will i end up with 2 sets of data requiring twice the storage space?
 
Soldato
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Arcserve UDP is essentially veeam but cheaper. It often gets a bad reaction because of the Arcserve name, but it's absolutely brilliant....i was actually the first customer to install it in the UK when it was released 2 years ago! :D

I have headaches with ArcServe UDP every, single, day. Nothing changes and yet backups fail for whatever reason. Usually have to restart the agent on the guest to get it going again. ArcServe support is the worst I have ever come across from a supplier. /rant :p

For what its worth we use in guest iSCSI across all of our VM's and have 0 issues. I was not aware there was a better or more recommended way of presenting LUN's. We have a Pure Storage SAN and an HP LeftHand P4800 and both present in the same fashion, depending on the type of data being stored. Datastores are obviously presented directly to ESXi but our Exchange data is presented as in guest iSCSI.

Are you doing dedupe on the ArcServe datastores via Windows AND via Arcserve? This would be why your stats are all over the place. ArcServe does inline compression and dedupe (actually does it very well) where as Windows has a scheduled job to run (as you know for garbage collection and optimisation) so can take hours or days, depending on your data size, for it to work through.
 
Soldato
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I have headaches with ArcServe UDP every, single, day. Nothing changes and yet backups fail for whatever reason. Usually have to restart the agent on the guest to get it going again. ArcServe support is the worst I have ever come across from a supplier. /rant :p

For what its worth we use in guest iSCSI across all of our VM's and have 0 issues. I was not aware there was a better or more recommended way of presenting LUN's. We have a Pure Storage SAN and an HP LeftHand P4800 and both present in the same fashion, depending on the type of data being stored. Datastores are obviously presented directly to ESXi but our Exchange data is presented as in guest iSCSI.

Are you doing dedupe on the ArcServe datastores via Windows AND via Arcserve? This would be why your stats are all over the place. ArcServe does inline compression and dedupe (actually does it very well) where as Windows has a scheduled job to run (as you know for garbage collection and optimisation) so can take hours or days, depending on your data size, for it to work through.

I've had a couple of encounters with arcserve support and found them to generally be pretty good myself, but for the most part i've found it just works and rarely has an issue. Updated to v6 yesterday too which went flawlessly.

I'm told that in guest iSCSI is essentially "the old fashioned way" since ESX5 fixed the 2TB volume issue, and that VMDK is often the way to go unless you're a special case.....of course that's from a new setup scenario, in terms of switching I'm not sure what the implications might be or the time it'll take, which is my worry.

The Data that's held within the in guest iSCSI datastores aren't backed up by UDP at the moment, only Arcserve Backup. I've told Arcserve backup to be dedupe aware via both the global and local settings as per arcserves documentation too.

I'm getting the feeling i might have to abandon the windows dedupe to be honest. It seemed a nice idea for some space savings, but it's not really saving me any space at all if it's not reliable :(
 
Soldato
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I'm getting the feeling i might have to abandon the windows dedupe to be honest. It seemed a nice idea for some space savings, but it's not really saving me any space at all if it's not reliable :(

Depends what you are trying to dedupe I guess. We get MASSIVE savings on our SQL backups but then we discovered SQL can compress when backing up via a maintenance plan (We had Brent Ozar do a deep dive on our SQL servers a while back and he pointed out a number of areas we could improve on) so once we turned that on we saw even more of a saving.

On our users home folders we found massive savings too as everyone seems to like storing data in their "My Documents" as well as on the corporate file share and everywhere else they can seem to find for it.

Your mileage will vary depending on your data trends I guess.
 
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