[ale] They say drives fail in pairs...

[gcs8]

Zfs raidz 1 raid 5ish

Zfs raidz 2 raid 6ish

Zfs raidz 3 adds a third parity drive.
On Jan 3, 2012 5:12 PM, "Ed Cashin" <ecashin at noserose.net> wrote:

> ZFS has a few mechanisms for redundancy, including a RAID 5-ish "raidz"
> and a RAID 10-ish stripe-of-mirrors scheme, but it also has checksums all
> over the place, multiple data copies, more flexibility, and on and on.
> It's complex but very neato.
>
> On Tue, Jan 3, 2012 at 4:52 PM, Lightner, Jeff <JLightner at water.com>wrote:
>
>> That confuses me.  Does ZFS have built in redundancy of some sort that
>> would obviate the need for the underlying storage to be hardware RAID?  Or
>> are you saying you'd use ZFS rather than Software RAID?
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: ale-bounces at ale.org [mailto:ale-bounces at ale.org] On Behalf Of
>> Michael Trausch
>> Sent: Tuesday, January 03, 2012 3:42 PM
>> To: Atlanta Linux Enthusiasts
>> Subject: Re: [ale] They say drives fail in pairs...
>>
>> On 01/03/2012 03:39 PM, Michael Trausch wrote:
>> > I am trying to figure out what I am going to do next with this setup.  I
>> > want to move the bulk of the data out of the office and onto a setup
>> > that can sustain about 50/50 read/write.  (It is more or less even; the
>> > humans mostly read, and automatic processes mostly write, a lot.)
>>
>> Actually, I am pretty sure that I am absolutely not going to use RAID.
>> I'm probably going to use ZFS on FreeBSD, or btrfs on Linux (if it ever
>> grows up and handles multiple devices without crapping all over you)
>> instead of RAID stuff.  Because both btrfs and ZFS can grow and shrink
>> dynamically, and they can take care of what amounts to RAID-like
>> functionality at the filesystem level, they seem to be much better for
>> things where you might be adding space on-demand.  The RAID stuffs are
>> very difficult to grow or reshape with time, and the needs of a small
>> business with big data storage requirements just don't mesh with RAID
>> all that well.
>>
>>        --- Mike
>>
>> --
>> A man who reasons deliberately, manages it better after studying Logic
>> than he could before, if he is sincere about it and has common sense.
>>                                   --- Carveth Read, "Logic"
>>
>>
>>
>>
>>
>> Athena(r), Created for the Cause(tm)
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>>
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>
>
>
> --
>   Ed Cashin <ecashin at noserose.net>
>   http://noserose.net/e/
>   http://www.coraid.com/
>
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