Date: Mon, 30 Sep 2002 15:22:48 +0100 From: Matthew Seaman <m.seaman@infracaninophile.co.uk> To: "Marc G. Fournier" <scrappy@hub.org> Cc: Matthew Seaman <m.seaman@infracaninophile.co.uk>, Giorgos Keramidas <keramida@FreeBSD.ORG>, freebsd-questions@FreeBSD.ORG Subject: Re: Per directory disk quotas ... Message-ID: <20020930142248.GA81795@happy-idiot-talk.infracaninophi> In-Reply-To: <20020930100742.I69855-100000@hub.org> References: <20020930095230.GB51277@happy-idiot-talk.infracaninophi> <20020930100742.I69855-100000@hub.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Mon, Sep 30, 2002 at 10:12:37AM -0300, Marc G. Fournier wrote:
> On Mon, 30 Sep 2002, Matthew Seaman wrote:
>
> > disks of the right size, which you can then put a filesystem onto and
> > mount in the correct place. I've seen reports that this technique
> > works very well to limit the amount of space a jail(8) can use even if
> > the jail's owner has full control over the password file in it.
>
> Neat, never thought of that ... only issue I could see with using
> something like that is that there appears to be no way of 'growing' the
> file system if required ... but still, a route to look at ...
I believe that disklabel(8) and growfs(8) work just as well on vnode
devices as on regular drives. And that unlike a regular drive, it's
pretty simple to dd(1) some extra space onto the end of the file...
In fact, let me try that:
I've created a 128Mb vn device on /dev/vn0a, put a file system on
it, mounted it and copied in a bunch of log files:
happy-idiot-talk:/mnt/vn0mnt:# df -kh /mnt/vn0mnt
Filesystem Size Used Avail Capacity Mounted on
/dev/vn0a 124M 136K 114M 0% /mnt/vn0mnt
happy-idiot-talk:/mnt/vn0mnt:# disklabel -r /dev/vn0
# /dev/vn0:
type: unknown
disk: amnesiac
label:
flags:
bytes/sector: 512
sectors/track: 32
tracks/cylinder: 64
sectors/cylinder: 2048
cylinders: 128
sectors/unit: 262144
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0 # milliseconds
track-to-track seek: 0 # milliseconds
drivedata: 0
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 262144 0 4.2BSD 1024 8192 22 # (Cyl. 0 - 127)
c: 262144 0 unused 0 0 # (Cyl. 0 - 127)
happy-idiot-talk:/mnt/vn0mnt:# ls -l
total 135
-rw-r--r-- 1 root wheel 54681 Sep 30 15:05 messages
-rw-r--r-- 1 root wheel 15743 Sep 30 15:05 messages.0.gz
-rw-r--r-- 1 root wheel 11631 Sep 30 15:05 messages.1.gz
-rw-r--r-- 1 root wheel 11253 Sep 30 15:05 messages.2.gz
-rw-r--r-- 1 root wheel 11804 Sep 30 15:05 messages.3.gz
-rw-r--r-- 1 root wheel 14268 Sep 30 15:05 messages.4.gz
-rw-r--r-- 1 root wheel 15577 Sep 30 15:05 messages.5.gz
The aim is to expand that to 256Mb without trashing the contents...
happy-idiot-talk:/:# umount /mnt/vn0mnt
happy-idiot-talk:/:# vnconfig -u vn0
happy-idiot-talk:/:# dd if=/dev/zero bs=1m count=128 >> /home/vnodes/vn0backingstore
128+0 records in
128+0 records out
134217728 bytes transferred in 6.030322 secs (22257141 bytes/sec)
happy-idiot-talk:/:# vnconfig -s labels -c vn0 /home/vnodes/vn0backingstore
happy-idiot-talk:/:# disklabel -r -w vn0 auto
happy-idiot-talk:/:# disklabel -e vn0 [ add in 'a' partition data ]
happy-idiot-talk:/:# disklabel -r vn0
# /dev/vn0c:
type: unknown
disk: amnesiac
label:
flags:
bytes/sector: 512
sectors/track: 32
tracks/cylinder: 64
sectors/cylinder: 2048
cylinders: 256
sectors/unit: 524288
rpm: 3600
interleave: 1
trackskew: 0
cylinderskew: 0
headswitch: 0 # milliseconds
track-to-track seek: 0 # milliseconds
drivedata: 0
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 524288 0 4.2BSD 1024 8192 22 # (Cyl. 0 - 255)
c: 524288 0 unused 0 0 # (Cyl. 0 - 255)
happy-idiot-talk:/:# growfs -y -s 524288 /dev/vn0a
new filesystemsize is: 262144 frags
growfs: 524288 sectors in 128 cylinders of 1 tracks, 4096 sectors
256.0MB in 6 cyl groups (22 c/g, 44.00MB/g, 10624 i/g)
super-block backups (for fsck -b #) at:
270368, 360480, 450592
happy-idiot-talk:/:# fsck /dev/vn0a
** /dev/vn0a
** Last Mounted on /mnt/vn0mnt
** Phase 1 - Check Blocks and Sizes
** Phase 2 - Check Pathnames
** Phase 3 - Check Connectivity
** Phase 4 - Check Reference Counts
** Phase 5 - Check Cyl groups
8 files, 136 used, 253927 free (7 frags, 31740 blocks, 0.0% fragmentation)
happy-idiot-talk:/:# mount -t ufs /dev/vn0a /mnt/vn0mnt
happy-idiot-talk:/:# cd /mnt/vn0mnt
happy-idiot-talk:/mnt/vn0mnt:# df -kh .
Filesystem Size Used Avail Capacity Mounted on
/dev/vn0a 248M 136K 228M 0% /mnt/vn0mnt
happy-idiot-talk:/mnt/vn0mnt:# ls -la
total 137
drwxr-xr-x 2 root wheel 512 Sep 30 15:05 ./
drwxr-xr-x 3 root wheel 512 Sep 30 15:00 ../
-rw-r--r-- 1 root wheel 54681 Sep 30 15:05 messages
-rw-r--r-- 1 root wheel 15743 Sep 30 15:05 messages.0.gz
-rw-r--r-- 1 root wheel 11631 Sep 30 15:05 messages.1.gz
-rw-r--r-- 1 root wheel 11253 Sep 30 15:05 messages.2.gz
-rw-r--r-- 1 root wheel 11804 Sep 30 15:05 messages.3.gz
-rw-r--r-- 1 root wheel 14268 Sep 30 15:05 messages.4.gz
-rw-r--r-- 1 root wheel 15577 Sep 30 15:05 messages.5.gz
So, success. The only gotchas seem to be:
i) You've got to unconfigure and the reconfigure /dev/vn0 before
it will pick up the new size of the backing store.
ii) You should use disklabel to add a partition of type 4.2BSD
rather than just using the /dev/vn0c whole "disk" partition
that's automatically created --- growfs(8) will only operate on
4.2BSD partitions.
iii) growfs(8) has to be told the new size of the filesystem, rather
than picking it up automatically.
Cheers,
Matthew
--
Dr Matthew J Seaman MA, D.Phil. 26 The Paddocks
Savill Way
Marlow
Tel: +44 1628 476614 Bucks., SL7 1TH UK
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20020930142248.GA81795>