Date: Wed, 12 Mar 2008 19:44:22 +0100 From: Angelo Turetta <aturetta@bestunion.it> To: freebsd-questions@freebsd.org Subject: UFS2 optimization for many small files Message-ID: <47D82486.5060402@bestunion.it>
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I recently upgraded the disk of my mail server. The server was initially
installed with a single 36GB RAID1 volume with FreeBSD 5 (summer 2004).
Over the years I upgraded to FreeBSD 6, and some months ago I added
another 36GB RAID1 volume and one 72GB RAID1 volume.
I then proceeded to copy my cyrus-imapd partition from /usr/local/mail
(on /dev/da0s1f) to the new 76GB /mail (/dev/da2s1d). During this copy I
noticed the disk usage of the mailboxes (as reported by du(8)) growing
about 20% larger in the process. Please note that cyrus stores mailboxes
with 1 file per message, 1 directory per IMAP-folder, and the moved
files are in the order of the hundred-thousands, with half of them less
than 8 KB large.
I tried understanding where the difference was, but I cannot work-out
any cause in the file systems:
[root@mail /data]# disklabel da0s1
# /dev/da0s1:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
a: 524288 0 4.2BSD 2048 16384 32776
b: 4142832 524288 swap
c: 71119692 0 unused 0 0 # "raw" part,
don't edit
d: 4194304 4667120 4.2BSD 2048 16384 28552
e: 1048576 8861424 4.2BSD 2048 16384 8
f: 61209692 9910000 4.2BSD 2048 16384 28552
[root@mail /data]# disklabel da2s1
# /dev/da2s1:
8 partitions:
# size offset fstype [fsize bsize bps/cpg]
c: 142253248 0 unused 0 0 # "raw" part,
don't edit
d: 142253248 0 4.2BSD 2048 16384 28552
What can I look at, now?
Should I decide to reformat my disk, what newfs parameters you'd advice
for my case?
Thanks,
Angelo.
PS: here follows the disk definitions: why the disk formatted during the
initial FreeBSD5 setup (da0) has a different geometry than the one
formatted later with FreeBSD6 (da1, hardware identical to da0)? Maybe
this is influencing the block occupation?
---------------------------------------------------------------------
[root@mail /data]# fdisk /dev/da0
******* Working on device /dev/da0 *******
parameters extracted from in-core disklabel are:
cylinders=4427 heads=255 sectors/track=63 (16065 blks/cyl)
Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=4427 heads=255 sectors/track=63 (16065 blks/cyl)
Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
start 63, size 71119692 (34726 Meg), flag 80 (active)
beg: cyl 0/ head 1/ sector 1;
end: cyl 1023/ head 254/ sector 63
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>
-----------------------------------------------------------------------
[root@mail /data]# fdisk /dev/da1
******* Working on device /dev/da1 *******
parameters extracted from in-core disklabel are:
cylinders=8716 heads=255 sectors/track=32 (8160 blks/cyl)
Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=8716 heads=255 sectors/track=32 (8160 blks/cyl)
Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
start 32, size 71122528 (34727 Meg), flag 80 (active)
beg: cyl 0/ head 1/ sector 1;
end: cyl 1023/ head 254/ sector 32
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>
-----------------------------------------------------------------------
[root@mail /data]# fdisk /dev/da2
******* Working on device /dev/da2 *******
parameters extracted from in-core disklabel are:
cylinders=17433 heads=255 sectors/track=32 (8160 blks/cyl)
Figures below won't work with BIOS for partitions not in cyl 1
parameters to be used for BIOS calculations are:
cylinders=17433 heads=255 sectors/track=32 (8160 blks/cyl)
Media sector size is 512
Warning: BIOS sector numbering starts with sector 1
Information from DOS bootblock is:
The data for partition 1 is:
sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD)
start 32, size 142253248 (69459 Meg), flag 80 (active)
beg: cyl 0/ head 1/ sector 1;
end: cyl 1023/ head 254/ sector 32
The data for partition 2 is:
<UNUSED>
The data for partition 3 is:
<UNUSED>
The data for partition 4 is:
<UNUSED>
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