Shared Transfer Server Storage for vcloud director cells

[ranvir09]

Hello ,

I am going to build an vCloud director cluster (3 hosts)in our environemnt but i was wondering about Shared Transfer Server Storage which is required for Uploads and downloads the data among all the cells, Below is the excerpts from Cloud director installation guide for the same

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To provide temporary storage for uploads and downloads, shared storage must be accessible to all hosts in a Cloud Director cluster. The transfer server storage volume must have write permission for root. Each host must mount this storage at $VCLOUD_HOME

/data/transfer(typically /opt/vmware/cloud-director/data/transfer). Uploads and downloads occupy this storage for a short time (a few hours to a day), but because transferred images can be large, allocate at least several hundred gigabytes to this volume.

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I have some queries related to this,

1. Can i use iSCSI storage volume for this "Shared Transfer Server Storage" or only NFS storage will do.

2. Which storage is recommended as per VMware prospective.

3. If someone have  any pointers to configuraton documentation  for this storage ,Please let me know.

Thanks

Ranvir

[pic]

> 1. Can i use iSCSI storage volume for this "Shared Transfer Server Storage" or only NFS storage will do.

Only NFS.  iSCSI is a block-level storage protocol so only one host can typically manage the blocks at a time.

> 2. Which storage is recommended as per VMware prospective.

If you're asking which storage given the choice of iSCSI and NFS, then NFS.  It's pretty much a requirement.  VMware does not recommend any particular vendor's storage device.  Or just use any server OS.  Just about every flavor of 'nix or windows server oses can support nfs.

> 3. If someone have any pointers to configuraton documentation for this storage ,Please let me know.

By configuration, if you mean how to create an NFS datastore, there are ample examples online if you're using an open-source OS.  If you're using a hardware NAS appliance, just follow the directions of the appliance.

[ranvir09]

Thanks a lot Phil ,but i was wondering ,In VMware vCD documentation ,they have not mentioned specifically NFS storage which actually they should have instead of "shared storage must be accessible to all hosts in a Cloud Director cluster."

or is it me who did not get their point properly.

Thanks once again for yor help

Ranvir

[pic]

You are correct.  It is not explicitly stated.  But in the very same location where you copy/pasted info about the Transfer Server Storage, just below it is a table that indicates you need to have the ports for NFS open.

http://pubs.vmware.com/vcloud-director-1-0/install_config_guide/r_prereqs.html#1_6_9_1

I agree it should be explicitly stated, but that is only truly necessary in a multi-cell environment (which implies anything in production).

I'll see if I can get it added.

[efulton · Accepted solution]

It's not explicitly stated mostly because there are several options and alternatives.

NFS is far and away the easiest, and also the easiest to relate to; but CIFS, for example, would work.  As would any other filesystem-sharing technique that makes the blob of data both readable and writeable from all cells simultaneously.

iSCSI is not enough to actually say yes or no about.  If you have an iscsi lun shared to several cells, and make an ext3 filesystem on it, then the cells are going to tear the file system metadata to pieces in relatively short order, since ext3fs is not designed to be multi-hosted.

This is not a limitation of iSCSI, or a SAN lun, or tricks with vms to share the same vmdk file to multiple vms, it's the filesystem put on top of it.

[ranvir09]

@efulton: Thanks a lot for much needed explaination ...really appreciated.

Ranvir

[jasonboche]

I wrote a blog article on Expanding Transfer Server Storage  yesterday which you may or may not be interested in.  You can find that  article at the link below:

http://www.boche.net/blog/index.php/2011/12/05/expanding-vcloud-director-transfer-server-storage/