James Dickens wrote:
On 9/11/06, Matthew Ahrens <[EMAIL PROTECTED]> wrote:
B. DESCRIPTION
A new property will be added, 'copies', which specifies how many copies
of the given filesystem will be stored. Its value must be 1, 2, or 3.
Like other properties (eg. checksum, compression), it only affects
newly-written data. As such, it is recommended that the 'copies'
property be set at filesystem-creation time
(eg. 'zfs create -o copies=2 pool/fs').
would the user be held acountable for the space used by the extra
copies?
Doh! Sorry I forgot to address that. I'll amend the proposal and
manpage to include this information...
Yes, the space used by the extra copies will be accounted for, eg. in
stat(2), ls -s, df(1m), du(1), zfs list, and count against their quota.
so if a user has a 1GB quota and stores one 512MB file with
two copies activated, all his space will be used?
Yes, and as mentioned this will be reflected in all the space accounting
tools.
what happens if the
same user stores a file that is 756MB on the filesystem with multiple
copies enabled an a 1GB quota, does the save fail?
Yes, they will get ENOSPC and see that their filesystem is full.
How would the user
tell that his filesystem is full since all the tools he is used to
report he is using only 1/2 the space?
Any tool will report that in fact all space is being used.
Is there a way for the sysdmin to get rid of the excess copies should
disk space needs require it?
No, not without rewriting them. (This is the same behavior we have
today with the 'compression' and 'checksum' properties. It's a
long-term goal of ours to be able to go back and change these things
after the fact ("scrub them in", so to say), but with snapshots, this is
extremely nontrivial to do efficiently and without increasing the amount
of space used.)
If I start out 2 copies and later change it to on 1 copy, do the
files created before keep there 2 copies?
Yep, the property only affects newly-written data.
what happens if root needs to store a copy of an important file and
there is no space but there is space if extra copies are reclaimed?
They will get ENOSPC.
Will this be configurable behavior?
No.
--matt
_______________________________________________
zfs-discuss mailing list
zfs-discuss@opensolaris.org
http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
