On Tue, Feb 3, 2009 at 20:55, SQA <sqa...@gmail.com> wrote: > I set up a ZFS system on a Linux x86 box. > > [b]> zpool history > > History for 'raidpool': > 2009-01-15.17:12:48 zpool create -f raidpool raidz1 c4t1d0 c4t2d0 c4t3d0 > c4t4d0 c4t5d0 > 2009-01-15.17:15:54 zfs create -o mountpoint=/vol01 -o sharenfs=on -o > canmount=on raidpool/vol01[/b] > > I did not make the export (vol01) into a volume. I know you can set default > blocksizes when you create volumes but you cannot make them exportable NFS > exports. Thus, I did not make the NFS exports into volumes and I did not > specify a blocksize on the NFS exports. > > I am assuming that vol01 is using variable blocksizes because I did not > explicitly specify a blocksize. Thus, my assumption is that ZFS would use a > blocksize that is the the smallest power of 2 and the smallest blocksize is > 512 bytes while the biggest would be 128k > > I use the stat command to check the filesize, the blocksize, and the # of > blocks. > > I created a file that is exactly 512 bytes in size on /vol01 > > I do the following stat command: > [b]stat --printf "%n %b %B %s %o\n" * [/b] > > The %b is the number of blocks used, %B is the blocksize. > > The number of blocks changes after a few minutes after the file is created: > > # stat --printf "%n %b %B %s %o\n" * > file.512 [b]1[/b] 512 512 4096 > # stat --printf "%n %b %B %s %o\n" * > file.512 [b]1[/b] 512 512 4096 > # stat --printf "%n %b %B %s %o\n" * > file.512 [b]1[/b] 512 512 4096 > > Q1) Why does the # of blocks change after a few minutes? And why are we using > 3 blocks when the file is only 512 bytes in size (in other words, only 1 > block is needed)??? This makes it seem that the minimum blocksize isn't 512 > bytes but 1536 bytes.
You probably have a cut'n'paste error as all block numbers are 1 in your example. My guess is that the number of blocks are updated every 5 seconds. > > Q2) Is there a way to force ZFS to use 512 blocksizes? That means that if a > file is 512 bytes in size or smaller, it should only use 512 bytes -- the > number of blocks it uses should be 1. It is, or at least is is on my solaris system. But it has to store metadata in one block. Try creating a 600 byte file and it should use one more 512 byte block. _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
