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Re: [Xen-users] NFS vs SMb vs iSCSI for remote backup mounts

Rudi Ahlers wrote:

ok, forget about rsync. forget about how I get the data onto the order server. WHICH filesystem would be best for this type of operation? SMB, NFS, or iSCSI?

As already stated, iSCSI is **NOT** a filesystem or a share of a filesystem - it is a network block device. You CANNOT share an iSCSI volume between multiple guests without running a cluster filesystem. If you use iSCSI, then you need to do one of three things :
1) Use a cluster file system on all the guests
2) Use a separate volume for each guest
3) Come up with some form of locking mechanism to allow one guest at a time to mount the volume Mounting a volume on two guests without a cluster file system is guaranteed to trash the filesystem on the volume.

As to SMB vs NFS, a lot depends on the filesystem semantics your backup process needs. SMB should support WIndows file system sematics/metadata, NFS only supports Unix file system semantics/metadata. If that matters then the decision is made for you - eg if the backup is storing Windows files natively on the backup filesystem then you'll have to use SMB in order to retain the file metadata.

Also, when comparing (or asking about) file system performance, you need to specify the conditions. Performance is likely to be different between a setup storing individual files (ie lots of create,write,close,update directory operations) and a single large archive setup (ie where the backup program creates a big file and streams the backup data into it).
I don't personally have any data on this either way.

--
Simon Hobson

WANTED: "Software CD ROM Kit" for Canon CLBP 360-PS printer (Canon part no RH6-3612, or possibly RH6-3810, or RH6-3610 might do). I've a dead HD and need this CD so I can replace the disk and re-install the printer OS on it. If anyone knows where I might get hold of one I'd be grateful - requests to Canon drew a blank, it's been out of support for years. Alternatively, if anyone has one of these and would let me image their hard disk ...

Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
author Gladys Hobson. Novels - poetry - short stories - ideal as
Christmas stocking fillers. Some available as e-books.

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