UFS2 tuning for heterogeneous 4TB file system

b. f. bf1783 at googlemail.com
Sun Jul 26 07:56:51 UTC 2009

>The file system in question will not have a common file size (which is
>what, as I understand, bytes per inode should be tuned for). There
>will be many small files (< 10 KB) and many large ones (> 500 MB). A
>similar, in terms of content, 2TB ntfs file system on another server
>has an average file size of about 26 MB with 59,246 files.

Ordinarily, it may have a large variation in file sizes,  but can you
intervene, and segregate large and small files in separate
filesystems, so that you can optimize the settings for each

>Ideally, I would prefer that small files do not waste more than 4 KB
>of space, which is what you have with ntfs. At the same time, having
>fsck running for days after an unclean shutdown is also not a good
>option (I always disable background checking). From what I've gathered
>so far, the two requirements are at the opposite ends in terms of file
>system optimization.

I gather you are trying to be conservative, but have you considered
using gjournal(8)?  At least for the filesystems with many small
files?  In that way, you could safely avoid the need for most if not
all use of fsck(8), and, as an adjunct benefit, you would be able to
operate on the small files more quickly:


gjournal has a lower overhead than ZFS, and has proven to be fairly
reliable.  Also, you can always unhook it and revert to plain UFS
mounts easily.


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