Hi Guys 1. As you hinted, this has changed with fractional reservations. (I'm not going into details now.)
2. Actually, you can easily resize a LUN. It makes no difference whether it's iSCSI or FCP. Do a "lun resize /vol/volname/lunname xxxg" where xxx is a size bigger than it was. Then rescan in VMware and add an extent to the VMFS using the fresh space in the LUN. For RDM, it depends on the guest OS (and its file system). Whether extents are a good practice is subject to a little debate.
3. This is certainly true. It gives more flexibility with NDMP and allows you to use a Linux server to achieve all the functionality of VCB and then some including loopback mount of vmdks. (Windows could also be used, but wouldn't be able to mount Linux FS's).
Share and enjoy!
Peter
-----Original Message----- From: Scott Lowe [mailto:slowe@EPLUS.com] Sent: Wednesday, July 11, 2007 7:44 AM To: Davies,Matt; toasters@mathworks.com Subject: NFS vs. iSCSI for VMware (was "Re: List still active?")
The #1 complaint I have about using iSCSI relates to how LUNs are handled in the NetApp world:
1. You have to (by default) allocate 2x + deltas for LUNs. For a 100GB LUN, you'd need 240GB of space (by default--I know there are workarounds with ONTAP 7.2 and later). With an NFS mount (which is nothing more than exporting a FlexVol), you only need to account for the 20% Snapshot reserve.
2. You can't resize iSCSI LUNs. With NFS on a FlexVol, you can resize to your heart's content because WAFL is controlling the filesystem--not the host.
3. It's open, meaning that your VMDKs aren't locked into the proprietary VMFS file system. This could potentially simplify backups and restores.
As Glenn @ Voyant already mentioned, you also gain thin provisioned disks by default and more knowledge/history/experience with NFS than with iSCSI.
Thanks, Scott Lowe ePlus Technology, Inc. slowe@eplus.com
On Jul 11, 2007, at 9:34 AM, Davies,Matt wrote:
Scott,
Any chance you could expand on the advantages of NFS over Iscsi ? NFS isn't an area I have any experience of....
Cheers
Matt
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner- toasters@mathworks.com] On Behalf Of Scott Lowe Sent: 11 July 2007 14:05 To: Forest Leonard; toasters@mathworks.com Subject: Re: List still active?
Forest,
When it comes time to configure VMkernel for VMotion, then I'd definitely recommend keeping it separate from the virtual machine network. As it stands right now, you don't even need a VMkernel NIC configured because it sounds like you are using Qlogic iSCSI HBAs and only have a single ESX Server. Since the Qlogic cards handle the iSCSI traffic and there is no VMotion, there no current need for a VMkernel NIC (unless you want to use NFS from the FAS to provide additional storage for VMs--which, by the way, works pretty well and has some nice advantages over iSCSI, IMHO).
Regards, Scott Lowe ePlus Technology, Inc. slowe@eplus.com
On Jul 11, 2007, at 8:33 AM, Forest Leonard wrote:
Interesting stuff. I only have one ESX server so I haven't gotten to the Vmotion configuration yet.. That should be later this year.
I just configured a RDM to run a Virtual server on. I found an article where you want to create the type as NTFS if it is a RDM for a windows host. Not sure if I am going to use this going forward. I actually don't know if you can migrate into a RDM. It doesn't look like it.
I am only using 2 NIC's on my Vmware server.. and a QLOGIC card for my ISCSI access.. I may need to look at bulking up my NIC configuration. It looks like I may gain some performance if I separate my VMKernal from my Virtual Machine network?
Thanks, Forest
-----Original Message----- From: Davies,Matt [mailto:MDAVIES@generalatlantic.com] Sent: Wednesday, July 11, 2007 8:18 AM To: Forest Leonard; ggwalker@mindspring.com; toasters@mathworks.com Subject: RE: List still active?
Sounds like we are both at the same stage.
We are not using RDM's yet, however when it comes to exchange we will
have to, or I may just stick with using the Microsoft Iscsi initiatator from within the VM, not exactly supported, but I know of other people doing it.
We have migrated 8 machines so far, into just one datastore and have not seen any performance problems at all, although most of the machines have very low IO requirements.
We are using a script to snapshot and then replicate using snapmirror, it works very well, however our Virtual Centre server is also a VM which was causing a few problems with the snapshots on the VMware side not being removed, but moving this to a separate datastore seems have cured the problems, even SQL doesn't seem to have a problem.
The script is the one written by Evan Battle, that is in the newest netapp docs on VMware. I did have a few problems with ssh to the filer, but we are now using rsh and it seems to be ok.
I don't know how you have setup your virtual switches on the ESX side, but I got some best practice information out of VMware on that subject.
Each of our ESX IBM3550 host servers have 6 Nics, connected as follows.
2 Nics for service console VMKernel for Vmotion, load balance using Virtual port ID
2 Nics for Virtual Machine network, load balance using Virtual port ID
2 Nics for ISCSI (Service Console and VMKernel), load balance using IP Hash
Hope this helps....
-----Original Message----- From: Forest Leonard [mailto:fleonard@rvigroup.com] Sent: 11 July 2007 11:06 To: Davies,Matt; ggwalker@mindspring.com; toasters@mathworks.com Subject: RE: List still active?
Hey Matt... I am actually doing the exact same thing on a FAS 270.. I
have migrated about 7 servers so far.
Are you using RDM's (remote device mappings) for the Virtual Machines? I actually just created 2 200GB LUNs on the netapp to use as Datastores and have not had any performance issues.
Just wondering what your experience with RDM's are.. I added one into
a virtual machine.. It just lets you map a LUN directly to a Virtual machine.
Has anyone out there used the netapp script to capture a VM snapshot?
Thanks, Forest
From: owner-toasters@mathworks.com on behalf of Davies,Matt Sent: Wed 7/11/2007 1:00 AM To: ggwalker@mindspring.com; toasters@mathworks.com Subject: RE: List still active?
Still working by the looks of things.
busy in process of migrating all our physical severs to VM, stored on
a iscsi lun on a FAS 270.
For those that want to know we are using the software iscsi initiator
within ESX and have not had any problems so far.
cheers
matt
-----Original Message----- From: owner-toasters@mathworks.com owner-toasters@mathworks.com To: toasters@mathworks.com toasters@mathworks.com Sent: Wed Jul 11 01:03:49 2007 Subject: List still active?
I've noticed that I'm still subscribed, but have received no email since July 4th. Everyone didn't trade their NetApp gear for something else while I was out of town did they?? J
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