Re: Trying to clone a ZFS drive, can't get ashift=12
On 01 Apr 2015, at 06:30, Daniel Eischen deisc...@freebsd.org wrote: I have an Oracle (nee Sun) X4-2 server with identical 300GB SAS drives. I did an MBR ZFS install from FreeBSD 10.1-RELEASE CD and have it updated to p6: ... # zpool create -o cachefile=/tmp/newpool.cache bootpoolNew label/boot0 # zdb -U /tmp/newpool.cache | grep ashift ashift: 9 What gives? How do I get it to use 4k? sysctl vfs.zfs.min_auto_ashift=12 And also put that in your /etc/sysctl.conf. I don't know why it isn't the default yet... :) -Dimitry signature.asc Description: Message signed with OpenPGP using GPGMail
Re: Trying to clone a ZFS drive, can't get ashift=12
On Wednesday, April 01, 2015 12:30:46 AM Daniel Eischen wrote: I have an Oracle (nee Sun) X4-2 server with identical 300GB SAS drives. I did an MBR ZFS install from FreeBSD 10.1-RELEASE CD and have it updated to p6: [..] # zpool create -o cachefile=/tmp/newpool.cache bootpoolNew label/boot0 # zdb -U /tmp/newpool.cache | grep ashift ashift: 9 What gives? How do I get it to use 4k? Before creating the pool, try: # sysctl vfs.zfs.min_auto_ashift=12 But watch your alignment of the MBR slices/partitions. I think you'll find it easier to manage with gpt for a data disk, eg: # gpart create -s gpt da1 # gpart add -t freebsd-zfs -a 4k da1 combine that with the sysctl above you should have everything on 4k. Setting -a just sets the rounding for the start/end sectors, it doesn't affect zfs when its sizing the sector size internally. btw; for a 300G drive you might not want 4k - this changes the base allocation size to be 8 times larger. You might find your space efficiency less than ideal if you have a lot of tiny files. -- Peter Wemm - pe...@wemm.org; pe...@freebsd.org; pe...@yahoo-inc.com; KI6FJV UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246 ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to freebsd-stable-unsubscr...@freebsd.org
Re: Trying to clone a ZFS drive, can't get ashift=12
On Tue, 31 Mar 2015, Peter Wemm wrote: On Wednesday, April 01, 2015 12:30:46 AM Daniel Eischen wrote: I have an Oracle (nee Sun) X4-2 server with identical 300GB SAS drives. I did an MBR ZFS install from FreeBSD 10.1-RELEASE CD and have it updated to p6: [..] # zpool create -o cachefile=/tmp/newpool.cache bootpoolNew label/boot0 # zdb -U /tmp/newpool.cache | grep ashift ashift: 9 What gives? How do I get it to use 4k? Before creating the pool, try: # sysctl vfs.zfs.min_auto_ashift=12 Thanks, and to Dmitri also. This seemed to do the trick. It is interesting that the default in the 10.1-RELEASE CD doesn't match the actual OS that is installed. But watch your alignment of the MBR slices/partitions. I think you'll find it easier to manage with gpt for a data disk, eg: # gpart create -s gpt da1 # gpart add -t freebsd-zfs -a 4k da1 combine that with the sysctl above you should have everything on 4k. Setting -a just sets the rounding for the start/end sectors, it doesn't affect zfs when its sizing the sector size internally. btw; for a 300G drive you might not want 4k - this changes the base allocation size to be 8 times larger. You might find your space efficiency less than ideal if you have a lot of tiny files. The server is a web server and poudriere package builder, with some postgres and mysql databases as backends for the web services. We don't anticipate user data or home/project directories. My first ZFS install was Solaris 11, which recommended (mandated?) that rpool be from a slice not an entire disk, and boot from an SMI (VTOC) disk. So I followed the same convention when installing FreeBSD. -- DE ___ freebsd-stable@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to freebsd-stable-unsubscr...@freebsd.org
