It might not work so well. Unionfs works based on files, it's unions
file system namespaces into a single namespace, but the restrictions of
each individual file system are still present.
If you have 3 4 TB file systems, the largest file size that could be is
4 TB. The other issue is that the you write to the topmost file system
(unless modifying an already existing file system) so it wouldn't use
the file system in the most efficient manner. You can get around this
by making a daemon that rotates the unioned layers around (if that suits
your purposes).
Ralf Gross wrote:
Hi,
we are starting to buy some large RAID arrays to store 50-100 TB of
video data. The data will later be processed by an application that
reads 2-3 video streams with ~16MB/s.
The storage will be attached to an Debian Etch Server (Kernel
2.6.18), the application/clients will access the data with samba.
The RAID array will be split in smaller volumes and I want to create
xfs filesystems on these volumes with a maximum size of 4TB.
With this we would end with 20-30 filesystems, which I think would not
be very feasible. Thus I would like to have one virtual filesystem (or
data area) which is exported as one share by samba.
Nobody would access the org. filesystems directly, only the virtual
unionfs.
I did a very quick test with unionfs and a couple of directories that
I mounted to a directory. This worked exactly as I wanted and seems to
be the solution I'm looking for.
Is there anything that could be a problem in this scenario, any
limitations?
I found this old posting:
unified storage
http://thread.gmane.org/gmane.comp.file-systems.unionfs.general/1070
Does that mean that I can't write 12 TB of data to a unionfs with 3 fs x
4 TB?
lvm is no option, because I need to create the filesystem on top of
lvm. And I really don't want to use fs >4TB.
Ralf
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_______________________________________________
unionfs mailing list: http://unionfs.filesystems.org/
[email protected]
http://www.fsl.cs.sunysb.edu/mailman/listinfo/unionfs
