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maximum size vmware iscsi datastore

I am trying to re-purpose an old backup server for backups from my VMWare machines. We are running the free version of VMWare ESXi 4.1.0.  Looking around I discovered that the only free iSCSI SAN software that works for my configuration is OpenFiler (and possibly FreeNAS).  So I have set up OpenFiler system with a 6.94TB LUN.

However when I attempt to create a datastore that big, VMWare maxes out the LUN at under 1TB. It looks like there is a limit of 2TB in the documentation. My goal is to attach this storage on a windows 2008 X64 vm that is running Backup Exec. (Because in the free ESXi I can't use the storage API).

I am looking for suggestions on how to attach this storage. Oh and what obvious facts am I missing as a storage nube?

-Rich
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DeepThnkr
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DeepThnkr
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5 Solutions
 
Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
The maximum size of a VMFS LUN is 2TB-512bytes, make it smaller as per the following doc.

Configuration Maximums for VMware vSphere 4.1
http://www.vmware.com/pdf/vsphere4/r41/vsp_41_config_max.pdf
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Create smaller LUNS, e.g. 3 x 2TB-512bytes each, and then Create Extents, and add them all together to create one LARGE VMFS 6TB datastore.

BUT BEwarned, if you lose one single LUN, the entire datastore will break.

OR Upgrade to ESXi 5.0, which does not have this limitation anymore with VMFS-5.

VMFS-5 Enhancements

    * Unified 1MB File Block Size. Previous versions of VMFS used 1,2,4 or 8MB file blocks. These larger blocks were needed to create large files (>256GB). These large blocks are no longer needed for large files on VMFS-5. Very large files can now be created on VMFS-5 using 1MB file blocks.

    * Large Single Extent Volumes. In previous versions of VMFS, the largest single extent was 2TB. With VMFS-5, this limit has been increased to ~ 60TB.

http://blogs.vmware.com/vsphere/2011/07/new-vsphere-50-storage-features-part-1-vmfs-5.html

Also make sure you set and format the blocksize correct, if using large files.

• 1MB block size – 256GB maximum file size
• 2MB block size – 512GB maximum file size
• 4MB block size – 1024GB maximum file size
• 8MB block size – 2048GB maximum file size
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Personally, Openfiler and FreeNAS are very poor when compared to ZFS on Solaris 11 Express, Openindiana, or Nexenta Core NAS.

All our FREE NAS solutions and offer iSCSI and NFS.
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kevinhsiehCommented:
Why don't you present the 6.94 TB LUN via iSCSI directly to the VM running BackupExec?
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
try this instead of BackupExec!

ghettoVCB
http://communities.vmware.com/docs/DOC-8760 ((Will work on FREE ESXi, no licensed required.)
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DeepThnkrAuthor Commented:
@kevinhsieh Thanks I think that is what I was missing.  If that is correct, I just attach to it from Windows and remove the Storage Adaptor from VMWare configuration?
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kevinhsiehCommented:
Probably (not a VMware guy).
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Yes, that is correct, just disable iSCSI Software Initiator on the ESXi server.

You can present the iSCSI LUN to a Windows Server, the size of the LUN is then based on NTFS limits. This LUN will then only be available to the WIndows VM.

You can use the iSCSI initiator in WIn2k8 R2.
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DeepThnkrAuthor Commented:
OK, Have to stop working on this and leave for the long weekend...  Thanks all for your comments.  I found that ideally I need to learn how to add a NIC to the VM that connects to the iSCSI SAN.  Also, the iSCSI initiator on the Windows side is not connecting to the resource.

As the VMWare virtual network for the iSCSI SAN was already created, and I can connect to my OpenFiler from it. The simplest path will probably be to create smaller LUNs and use extents. But I don't understand why when I create a datastore VMWare is shrinking that to under 1TB.  God bless storage geeks.
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Andrew Hancock (VMware vExpert / EE MVE^2)VMware and Virtualization ConsultantCommented:
Because VMware cannot support a LUN above 2TB-512bytes, it's an addressing function of the code, if a LUN is presented above 2TB-512bytes which is not supported, it gets confused.

Upgrade to ESXi 5.0! (also free download!)
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