Date: Thu, 17 Nov 2011 15:12:16 -0500 From: "list, mailing" <list@sprymed.com> To: Freddie Cash <fjwcash@gmail.com> Cc: "freebsd-performance@freebsd.org" <freebsd-performance@freebsd.org> Subject: Re: ZFS Few Questions Message-ID: <CAKy=mtB0Q6XApJ7vc3CCjyBAd9TjHxG0s85EV0x4mbhZZTJpxw@mail.gmail.com> In-Reply-To: <CAOjFWZ7oSE%2BMnFnTqi8tfb%2By3WN49cvqSWdMATS8770hzq9krg@mail.gmail.com> References: <CAKy=mtCcHavRFh16yaVH86Oh6DgePmxOhbQmmAySxWA5Zn8-yA@mail.gmail.com> <CAOjFWZ7oSE%2BMnFnTqi8tfb%2By3WN49cvqSWdMATS8770hzq9krg@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Wow. Great reply. Going to do some practice with mirror type and 9 RC 2. Thanks again On Thursday, November 17, 2011, Freddie Cash <fjwcash@gmail.com> wrote: > On Thu, Nov 17, 2011 at 10:26 AM, list, mailing <list@sprymed.com> wrote: >> >> Hello everyone I just had a few questions about ZFS. >> I normally use Hardware RAID 5. >> >> Question 1: >> >> With the ZFS snapshots what is the lost in drive spacoe? >> > > If no data changes after you create the snapshots, then no disk space is used by the snapshots. > If data changes after you create the snapshot, then the snapshot holds the original data. For example, if you have 100 GB in the filesystem, create a snapshot, then modify 10 GB of data, the snapshot will hold 10 GB of data (the original, unchanged data), and the total disk usage (filesystem + snapshot) is 110 GB. > >> >> Hard drives I have: >> 4 x 500 GB = 1.5T on RAID 5 >> >> I have see lots of videos like: ZFS is Smashing Baby > > With ZFS, you decide how much disk space you want to use for redundancy. With 4 harddrives, you have the following options: > 2x mirror vdev = 1.0 TB of usable space; best performance, can lose 2 drives before losing data > 1x raidz1 vdev = 1.5 TB of usable space; decent performance, can lose 1 drive before losing data > 1x raidz2 vdev = 1.0 TB of usable space; ok performance,, can lose 2 drives before losing data > raidz1 is similar to RAID5. raidz2 is similar to RAID6. > >> >> Question 2: >> >> FreeBSD 9.0 installable on ZFS root? > > Yes. > >> >> Question 3: >> >> Anyone Recommend for MySQL server? (Performance) > > Read through the ZFS Admin Guide for recommendations for running databases on top of ZFS. > >> >> Question 4: >> >> fsck used with when Server just turns off? (Fast or slower filesystem check >> when compared to UFS on HW RAID 5 ) >> Taking note of: "FreeBSD 9.0 adds support for lightweight journaling on top >> of softupdates(SU+J), which greatly reduces and need for background fsck, >> and uses NFS-style ACLs by default." >> > ZFS does not have a separate "fsck" tool. It does not need it. If the box crashes, ZFS will just come back online, possibly losing 5-10 seconds worth of uncommitted data. If ZFS is unable to come back online automatically, you can manually roll it back a transaction group or two. You'll lose a bit of data, but the filesystems will be coherent and intact and operational. > -- > Freddie Cash > fjwcash@gmail.com > -- Ben Adams http://www.SpryMed.com/
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?CAKy=mtB0Q6XApJ7vc3CCjyBAd9TjHxG0s85EV0x4mbhZZTJpxw>