<Linux geek out>
I like to raid my _partitions_ across drives.
Raid 1 for /boot (which means I can ALWAYS boot, even if all but 1 drive is
dead).
Raid 1, 10, 5 or 6 for / (depending on many factors)
and Raid 0 for swap.
While I have great respect for the various hardware raid companies and their
many features and strengths, a software raid is so much an improvement over no
raid at all. Linux's mdadm has been nothing but rock-solid for years and
extremely flexible. I am also looking forward to improved file systems such as
ZFS or Btrfs, with built in features such as automatic per-block checksum,
per-block data deduplication, copy-on-write, snapshotting and resilvering.
As a related note, finding out if a raid is faulty with Linux is easy. ("cat
/dev/mdstat") Finding out if a raid is faulty with windows... I hope you have
pre-configured your monitoring so it can monitor your Intel Matrix
raid/LSI/Adaptec/etc card correctly.
I only wish Windows had a decent software raid. Sadly, it seems Microsoft isn't
interested in this.
</Linux geek out>
--Matt Ross
Ephrata School District
----- Original Message -----
From: David [mailto:[email protected]]
To:
NT System Admin Issues [mailto:[email protected]]
Sent:
Fri, 16 Dec 2011 15:44:28 -0800
Subject: Re: Virtualization - Sizing, hard
disk config
> I supposed this is way too old-school, but I've always been a fan of RAID
> 1. I can always take one of the disks and get another machine back up if I
> have to.
>
> David
>
>
> On Fri, Dec 16, 2011 at 10:00 AM, Paul Hutchings
> <[email protected]>wrote:
>
> > If you take a RAID and move it from one controller to another you are a
> > braver man than I am :)
> > ________________________________________
> > From: Matthew W. Ross [[email protected]]
> > Sent: 16 December 2011 5:03 PM
> > To: NT System Admin Issues
> > Subject: Re: Virtualization - Sizing, hard disk config
> >
> > > Plus, not all controllers that will support RAID5 will support RAID50.
> >
> > As far as I can tell, there is NO controller cross compatibility with
> > RAID, right? I can't use a raid 10 on an Adaptec card and expect it to
> > cleanly transfer to a system with a LSI card, right?
> >
> > If I'm wrong, that's excellent. But I don't think that it's true at all.
> > Only a software solution can be compatible across hardware (i.e.: Linux's
> > mdadm can handle cross-hardware raid compatibility.)
> >
> >
> > --Matt Ross
> > Ephrata School District
> >
> >
> > ----- Original Message -----
> > From: Andrew S. Baker
> > [mailto:[email protected]]
> > To: NT System Admin Issues
> > [mailto:[email protected]]
> > Sent: Fri, 16 Dec 2011
> > 05:20:10 -0800
> > Subject: Re: Virtualization - Sizing, hard disk config
> >
> >
> > > Yes, rebuild time and overall data loss risk is worse with the RAID5
> > > variants. I'd sooner do RAID6 than RAID50.
> > >
> > > Plus, not all controllers that will support RAID5 will support RAID50.
> > >
> > > * *
> > >
> > > *ASB* *http://XeeMe.com/AndrewBaker* *Harnessing the Advantages of
> > > Technology for the SMB market…
> > >
> > > *
> > >
> > >
> > >
> > > On Thu, Dec 15, 2011 at 10:21 PM, Ben Scott <[email protected]>
> > wrote:
> > >
> > > > On Thu, Dec 15, 2011 at 9:20 PM, Bill Humphries <[email protected]
> > >
> > > > wrote:
> > > > > Seems everyone assumed RAID 10. Would you not consider
> > > > > RAID 50 if you had 8 SAS drives and decent controller with battery
> > > backed
> > > > > cache?
> > > >
> > > > (Sanity check: RAID 50 = RAID 0 of RAID 5's = stripe of
> > > > stripes-with-parity. You need at least three disks for RAID 5. So
> > > > with 8 disks, the only configuration that uses all of them would be
> > > > two 4-disk RAID 5 sets, then stripped with RAID 0. Yah?)
> > > >
> > > > My take is:
> > > >
> > > > With modern disk sizes, RAID 5 can be pretty horrible during a
> > > > rebuild. Say you've got 8 x 600 GB. 4 x 600 = 2400 GB, raw. Lose
> > > > one disk, replace it, and you have to read 1800 GB to rebuild that one
> > > > 600 GB missing member.
> > > >
> > > > And with the large disk sizes, the chances of a double failure are
> > > > higher, too. Sucks to find out there's a new bad block in that
> > > > remaining 1800 GB.
> > > >
> > > > RAID 10 is nice and simple: At most you're doing I or O on an entire
> > > > single disk. Plus it's much better in terms of I/O performance. Disk
> > > > usage efficiency is crap at 50%, but with the low cost of storage
> > > > these days, that's not as big a loss as it once was. And with only 8
> > > > disks, RAID 50 is only going to be 75% efficient, right?
> > > >
> > > > -- Ben
> > > >
> > > >
> > > >
> > >
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>
> _____________________
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> *
>
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