17 messages in org.freebsd.freebsd-fsAdvice for hacking on ufs/ffs| From | Sent On | Attachments |
|---|---|---|
| Shane Adams | Jul 24, 2006 6:51 pm | |
| Eric Anderson | Jul 24, 2006 7:06 pm | |
| Shane Adams | Jul 24, 2006 7:11 pm | |
| Shane Adams | Jul 24, 2006 7:41 pm | |
| Eric Anderson | Jul 24, 2006 7:50 pm | |
| Dag-Erling Smørgrav | Jul 25, 2006 3:12 pm | |
| Eric Anderson | Jul 25, 2006 4:12 pm | |
| Shane Adams | Jul 25, 2006 5:54 pm | |
| Rick C. Petty | Jul 25, 2006 6:33 pm | |
| Eric Anderson | Jul 25, 2006 6:39 pm | |
| Dag-Erling Smørgrav | Jul 25, 2006 6:49 pm | |
| Dag-Erling Smørgrav | Jul 27, 2006 7:14 am | |
| Rick C. Petty | Jul 27, 2006 5:54 pm | |
| Oliver Fromme | Jul 28, 2006 9:27 am | |
| Rick C. Petty | Jul 28, 2006 3:10 pm | |
| Shane Adams | Aug 1, 2006 8:54 pm | |
| Eric Anderson | Aug 2, 2006 3:44 am |
| Subject: | Advice for hacking on ufs/ffs | |
|---|---|---|
| From: | Oliver Fromme (ol...@lurza.secnetix.de) | |
| Date: | Jul 28, 2006 9:27:34 am | |
| List: | org.freebsd.freebsd-fs | |
Rick C. Petty wrote:
Dag-Erling Sm?rgrav wrote:
Rick C. Petty wrote:
Shane Adams wrote:
I used dd to create 1G file.
A faster way is: touch filename truncate -s 1g filename
no, this will result in a fragmented image, which will hurt run-time performance.
Indeed.
Not necessarily. If you install a variant of windoze, the installer will format the disk first, writing zeros (and metadata) sequentially, and thus the allocation will not be fragmented.
Not true. Last time I installed Windows, it did not overwrite the whole disk. If it did that, it would have taken _way_ too long (hours instead of minutes).
In the case of UFS newfs only the metadata will be written for each cylinder group
No. Only the superblock copies and block bitmaps are written during newfs, nothing else.
and thus the logical blocks for all metadata will be contiguous.
Nope. As soon as you start writing to such a file system, it will start allocating space for inodes, indirect block lists, directories and file data, which will probably lead to massive fragmentation.
Best regards Oliver
-- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way.
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