In a typical solution you lose 10% for WAFL overhead (disk serialization, mbr, etc). You then lose 5% for aggregate snap reserve and 20% for volume snap reserve. Actually, you don't lose the snap reserve space - this space is reserved to ensure enough space for typical snapshots (think of them as online backups). The snap reserve space can be changed. For instance, I always set the aggregate snap reserve to 0% -- I cannot foresee any situation where I would want to snap restore an entire aggregate. These numbers are for NAS. If you are using SAN (iSCSI or FCP LUNs) then you lose 50% of available space to be able to accommodate at least one full snapshot of the LUNs. To someone first starting out with NetApp solutions, these numbers sound horrible, I know I did. However, now that I've been using them for a few years I love it. The flexibility you get in disaster recovery, transferring data to other filers, etc is very much worth the tradeoff.
-----Original Message----- From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of margesimpson@hushmail.com Sent: Wednesday, July 26, 2006 9:38 PM To: toasters@mathworks.com Subject: Storage space overheads!
Hi all: Can anyone please give me total NetApp overheads including, file systems, aggr reserve, snap reserve, wafl overhead, parity disks (raid_dp), etc, etc. say, 10 x 100GB = 1000GB total. what usable space should i finally get after all those overheads.
Can anyone give me proper figures/ math and proper break up of above figure?
I heard NetApp solution has lot of disk overheads!
Thank you in advance. Marge.
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