Messages in this thread | | | From | "Stefan Monnier" <monnier+lists/linux/kernel/news/@tequila.cs.yale.edu> | Subject | Re: 2.3.x wish list? | Date | 23 May 1999 19:06:38 -0400 |
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>>>>> "Paul" == Paul M Hirsch <pauldoom@webcreate.net> writes: > Solaris and Irix (XFS) offer block sizes from 4KB to 8KB, and from 512B
Solaris' UFS (a derivative of BSD-4.3 ffs) doesn't treat its blocks in the same way as ext2 since it has fragments. This reduces considerably the space cost of 4KB blocks (at a complexity cost of course). IIRC, ext2's block allocation policy is sufficiently better than ffs that the it doesn't need as big a block size as ffs to reach the same performance, making fragments unnecessary.
My MH mailbox would look like: 70MB with 1KB-blocks 77MB with 2KB-blocks 96MB with 4KB-blocks
Since MH mailboxes are about as bad a case as it gets (apart possibly from big symlink-farms), it seems that 2KB is a safe default while 4KB incur a non-negligible space cost.
I don't know whether Irix's XFS has fragments (I believe it doesn't), but it does have "file in the inode" (not just for symlinks but also for files and directories) which might also reduce the need for small blocks. I also seem to remember that the recommended block size for "normal use" (non-multimedia, non-HPC) is below 4KB (which is another indication that it probably doesn't support fragments).
Stefan
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