stability of software RAID under Linux
Having spent a considerable amount of time trying to ascertain the stability of vinum under FreeBSD, i'm not confident in using it on a production box. I don't know much (at the moment about Linux Software RAID), but would like to hear people's experience. It's a RAID 5 solution that interests me running with a SMP kernel. As far as I can ascertain there are 2 RAID packages. LVM and the raidtools package and patches. Which is better, which is more stable? any experiences/tips greatly appreciated, thanks Darren -- Darren Evans Tel: +44(0)20 7700 9960 Systems, Profero Ltd Fax: +44(0)20 7700 9961
RE: stability of software RAID under Linux
Vinum is a LVM tool. The s/w RAID implementation for Linux is not an LVM tool, although RAID-0 could be used to striping/concat. Both LVM and RAID are expected to be in 2.4 so you can be pretty sure that it has been tested and since Linus has given his seal of approval, that's enough to convince me that it is stable. Marco -Original Message- From: Darren Evans [SMTP:[EMAIL PROTECTED]] Sent: May 26, 2000 11:49 AM To: [EMAIL PROTECTED] Subject: stability of software RAID under Linux Having spent a considerable amount of time trying to ascertain the stability of vinum under FreeBSD, i'm not confident in using it on a production box. I don't know much (at the moment about Linux Software RAID), but would like to hear people's experience. It's a RAID 5 solution that interests me running with a SMP kernel. As far as I can ascertain there are 2 RAID packages. LVM and the raidtools package and patches. Which is better, which is more stable? any experiences/tips greatly appreciated, thanks Darren -- Darren Evans Tel: +44(0)20 7700 9960 Systems, Profero Ltd Fax: +44(0)20 7700 9961
Re: stability of software RAID under Linux
On Fri, 26 May 2000, Darren Evans wrote:
Having spent a considerable amount of time trying to
ascertain the stability of vinum under FreeBSD, i'm not
confident in using it on a production box.
When I looked at Vinum last, it required some proprietary stuff from Veritas to
provide RAID-5 functionality. I don't know if that has been ``fixed'' by now,
but that certainly put me of.
I don't know much (at the moment about Linux Software RAID),
but would like to hear people's experience.
It's a RAID 5 solution that interests me running with
a SMP kernel.
All RAID levels with Ingo's patch are considered stable. They have all seen a
lot of testing, and are in production a lot of places.
I have 7 systems with RAID-1 or RAID-5 running, 6 in production, and having
seen disk failures being handled gracefully too, I have no doubts about using
Linux Software RAID for critical systems. In fact I usually recommend it for
critical systems.
It's not a silver bullet though. It won't magically fix that your chipset can
lock up if enough hardware goes bad enough. But it will usually save you from
bad blocks and the likes... Those are the errors you are _certain_ to meet at
some point.
As far as I can ascertain there are 2 RAID packages.
LVM and the raidtools package and patches. Which is
better, which is more stable?
LVM can't do redundancy. If you need flexible storage, go for LVM, if you need
reliable storage go for RAID-1 or RAID-5. You can, I presume, build a LVM over
RAID-1/5 arrays, although I have *no* experience with LVM what so ever (yet).
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Re: stability of software RAID under Linux
On Fri, 26 May 2000, Darren Evans wrote: Having spent a considerable amount of time trying to ascertain the stability of vinum under FreeBSD, i'm not confident in using it on a production box. I don't know much (at the moment about Linux Software RAID), but would like to hear people's experience. It's a RAID 5 solution that interests me running with a SMP kernel. In my opinion Linux SW Raid is very stable. However, SW raid stresses SCSI to its limit and any tiny error in the hardware will show up very quickly. Also, not all drivers handle the situation when a disk dies, they hang up the bus. As far as I know the NCR/Symbios- and AIC7xxx-driver will not hang up the bus. ECC-Ram is also a must. As far as I can ascertain there are 2 RAID packages. LVM and the raidtools package and patches. Which is better, which is more stable? Those are two completely different things. Holger
Re: stability of software RAID under Linux
Holger Kiehl wrote: In my opinion Linux SW Raid is very stable. However, SW raid stresses SCSI to its limit and any tiny error in the hardware As does HW Raid. No matter how you saturate your SCSI bus, its saturated. will show up very quickly. Also, not all drivers handle the situation when a disk dies, they hang up the bus. As far as I know the NCR/Symbios- and AIC7xxx-driver will not hang up the bus. ECC-Ram is also a must. I wouldn't say that ECC-RAM is a must for RAID systems - if you need it, you need it. -- Edward Schernau,mailto:[EMAIL PROTECTED] Network Architect http://www.schernau.com RC5-64#: 243249 e-gold acct #:131897
Re: stability of software RAID under Linux
On Fri, 26 May 2000, Edward Schernau wrote: I wouldn't say that ECC-RAM is a must for RAID systems - if you need it, you need it. Ok, its not required, but if you do care about your data I would strongly recommend it for SW raid. Holger
