Date: Tue, 09 Dec 2008 10:58:25 +0100 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-fs@freebsd.org Subject: Re: ZFS resize disk vdev Message-ID: <ghlfg0$lpd$1@ger.gmane.org> In-Reply-To: <493E12EC.4050801@modulus.org> References: <92f477740812082155y3365bec7v5574206dd1a98e26@mail.gmail.com> <493E12EC.4050801@modulus.org>
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[-- Attachment #1 --] Andrew Snow wrote: > Bryan Alves wrote: >> I'm thinking about using a hardware raid array with ZFS, using a >> single disk >> vdev zpool. I want the ability to add/remove disks to an array, and I'm >> still unsure of the stability of zfs as a whole. I'm looking for an easy >> way to resize and manage disks that are greater than 2 terabytes. >> If I have a single block device, /dev/da0, on my system that is >> represented >> by a zfs disk vdev, and the size of this block device grows (because the >> underlying hardware raid expands), will zfs correctly expand? And >> will it >> correctly expand in place? > > In theory, this works fine - I have never tried it myself. The only > other way to expand a zpool is by adding more vdevs: You cannot change > a vdev once it is created other than to take it from a single disk to a > mirror. > > Sun's ZFS best practice guide states that you should avoid a single disk > vdev because performance on the whole suffers and is worse than UFS. > > I am going to publish some benchmark figures soon to back this up, based > on testing I did with a 16 disk hardware RAID6. ZFS was *alot* faster > when I gave it the disks in a RAIDZ2 vdev. You mean it was a lot faster *per disk*, right? (otherwise, it's completely expected that a large RAID array will be faster than its components). [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFJPkFBldnAQVacBcgRAmUcAKC84K4yUtlV8TCdG6SJla1xQbKSMACgpEk0 CTNOcJLtr1GTLyA/qLKz2W8= =xy03 -----END PGP SIGNATURE-----
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