How reliable is RAID ARRAY 5?

[leg4]

?How reliable is RAID ARRAY 5?

thanks

[SuckOnThis]

If you're talking in terms of data loss in case a drive goes not very. I had a drive go down with RAID 5 and lost everything.

[synapse]

by definition it's *the* most reliable disk config slower then say RAID 0 / 1 but solid.

[leg4]

Then what is it good for???

How did you lose all your data with RAID?

[Machete_]

Raid is one of the safest.. if you lose one drive, you will continue running, if the software is set up correct... A lot of breakdowns happend when unskilled personals try to bring the raid online again.

Of you have more than 8 raidsets, its also the fastest kombination of disks. I have 13 seperate workstations with its own 2mb/s throughput to the 1.4 TB SAN - even if one disk is down - that is only possible with raid5.

[leg4]

Raid 0... yes.... but other RAIDS... arent they reliable?

[Machete_]

If you're talking in terms of data loss in case a drive goes not very. I had a drive go down with RAID 5 and lost everything.

then you need to replace your tech guys.... The raid info is written to the disk, so if only one disk broke down, you would be REALLY incompetent if you could not rebuild a Raid5

[Machete_]

Raid 0... yes.... but other RAIDS... arent they reliable?

I WAS talking about raid5...
and yes they are. its only bad personel that can fuck it up

[Brad Mitchell]

then you need to replace your tech guys.... The raid info is written to the disk, so if only one disk broke down, you would be REALLY incompetent if you could not rebuild a Raid5

As a host myself, I would say anything is possible. As a host, I would say a RAID 5 is a great choice for the best mixture of price and reliability. Other things to consider are what type of drives are being used and what type of RAID controller - they're not all created equal. No hardware solution is infalliable, that's why I always recommend a full backup - even of large RAID volumes. If you want some recommendations on hardware simply email me or call me during the day.

Cheers,

Brad

[leg4]

I made a huge mistake.. I got my first RAID system a few months ago... not knowing much about RAIDS.... I prebuilt with DELL online and got a RAID 0 (I didn't know any better...)

2.5 months later.... It shuts down and will not reboot....

Maxtor Calypso drives... are these crappy Maxtors?

[Machete_]

As a host myself, I would say anything is possible. As a host, I would say a RAID 5 is a great choice for the best mixture of price and reliability. Other things to consider are what type of drives are being used and what type of RAID controller - they're not all created equal. No hardware solution is infalliable, that's why I always recommend a full backup - even of large RAID volumes. If you want some recommendations on hardware simply email me or call me during the day.

Cheers,

Brad

agree on the backup 100%... raid wont safe you from flooding or explosions.
We run a HP ETLA - cost us 1,5mill but if our customer breakdown, there will be no national TV in denmark.

[Machete_]

I made a huge mistake.. I got my first RAID system a few months ago... not knowing much about RAIDS.... I prebuilt with DELL online and got a RAID 0 (I didn't know any better...)

2.5 months later.... It shuts down and will not reboot....

Maxtor Calypso drives... are these crappy Maxtors?

never ever what so ever, put your OS on a Raid 0.. you have 75% higher chance of breakdown...

If you want something fast, then buy 4 disks:
Make one raid1 set out of disk 1 and 2 - call it A
Make one raid1 set out of disk 3 and 4 - call it B

Connect 1 and 3 to one channel on the raidcontroller
connect 2 and 4 to the other channel

Make a raid 0 (stripe) out of set A and B - that way you have SUPER speed and safety.. 2 disks have to die before you loos data that way . and it got the speed of a raid0

[leg4]

I can't believe those fucking hahahahaS at Dell sold me a big server with my system (C) drive on RAID 0--- fucking hahahaha heads

[jimmyf]

I WAS talking about raid5...
and yes they are. its only bad personel that can fuck it up

my understanding is that raid5 is the best, someone else post
raid5 was NO good.

but what do I know, started in computers before XT days.

[SuckOnThis]

then you need to replace your tech guys.... The raid info is written to the disk, so if only one disk broke down, you would be REALLY incompetent if you could not rebuild a Raid5

Yep, you are correct, and I replaced them when it happened 3 years ago, and I should have sued the hell out of them. The hosting company sold me on the RAID 5, purchased the server from them, and when the disk failed they replaced it without my permission or even telling me it went down. All I knew was I get a phone call from them telling me all my data was lost. I had a backup that was about 30 days old because they assured me with RAID 5 there wouldnt be a data loss if a disk failed. So I'm sure it was their incompetence. Then the fuckers had the nerve to try to charge me $2000 for tech support. Cost me over $10,000 because of the downtime. Live and learn.

[Machete_]

I can't believe those fucking hahahahaS at Dell sold me a big server with my system (C) drive on RAID 0--- fucking hahahaha heads

Are people in the US buying preconfigured windows server? WTF? servers need to be customiced to the usrs needs... MTF/clustersize/log or else you COULD lose 50% preformance

[leg4]

Actually, it wasn't a server.... it was an editing system.... My bad dawg!

[Machete_]

Yep, you are correct, and I replaced them when it happened 3 years ago, and I should have sued the hell out of them. The hosting company sold me on the RAID 5, purchased the server from them, and when the disk failed they replaced it without my permission or even telling me it went down. All I knew was I get a phone call from them telling me all my data was lost. I had a backup that was about 30 days old because they assured me with RAID 5 there wouldnt be a data loss if a disk failed. So I'm sure it was their incompetence. Then the fuckers had the nerve to try to charge me $2000 for tech support. Cost me over $10,000 because of the downtime. Live and learn.

woooww !!!
On each of our lage customers, we write up an ensurance for dataloss - depending on what equipment they have, and what level of access the users and local admin have. Next time you hire external help - ask for the same
that would be my free advice to you

[toddler]

RAID 5 is fine if you know what you are doing, or your tech folks do. RAID 0 is just slapping the drives together to make one logical LUN to the OS, which is worthless for business continuity.

The real question is: what are the pertinent differences between RAID 0+1 and 1+0. No google allowed

[Brad Mitchell]

ebus - what you were saying about doing two raid ones and joining those together with a zero, that's a raid 10. Very cool, just more expensive because you need twice the drives for capacity.

RAID 0 definitely has it's place. In load balanced environments, like we have for some of our clients, it might look something like 3 to 5 identical servers each running on a RAID 0. If one of the servers RAID fails it's not a big deal, the others pick up the load until a replacement can be put online. That's a sweet setup for speed. But, it would still be incomplete without a backup.

RAID 5 instability doesn't have to have anything to do with the technicians supporting it. Even with great techs, two drives can fail at once or a controller can equally screw up and cause data loss or complete failure. A better than average RAID 5 would have an additional hot-spare in the configuration so that when a problem is encountered time is less of the essence.

RAID 1 is practical for medium and low volume servers if it's configured properly. This has two drives mirroring. What you lose is some performance... also, it's not really a backup. If data on a drive gets corrupted then that just gets replicated to the other drive. So, the lesson is
always the same - have a backup.

My advice is always the same:

1) Have a backup locally and if possible, have one at your host too.
2) Do routine checks on drive and volume health so that you can spot the "average" problem from a mile away. Much better to be fixing something before it breaks!

Brad

[Machete_]

ebus - what you were saying about doing two raid ones and joining those together with a zero, that's a raid 10. Very cool, just more expensive because you need twice the drives for capacity.

Brad

Yep - again we agree. But If you need both speed and safety without paying for a LARGE setup, this is the way.

and sure, we use raid0 as well... but not mission critical stuff.. and examble would be temp. sourvematerisl for videoediting, and then storeing metadate on the san. But Most our stuff is NSPF (No single point of Faliure )

[TheSaint]

Raid 5 in theory is 100% reliable - unless you loose 2 disks at once - but in practice as said with crap hardware, crap software, or crap techs you can loose everything. You still need to backup daily and weekly and have multiple backups offsite, etc.. People not familiar with IT don't understand that RAID has nothing to do with backup, you can still remove every file on the disk by accident with one mistyped command.

Over the years I have lost disks more than once with raid-5 or raid-1 and safely recovered by replacing the disk. I always configure raid-5 with one or more spares (besides the parity disk). That way when a drive goes out a spare is swapped in automatically - to avoid the remote chance of a second failure before you can replace the first one.

[MickeyG]

I've lost two drives at once on a raid 5 system, so make sure to use backups.

[leg4]

Thanks for all the great tips, info, news and stuff that you shared with me fellaz....


Who wants a beer? Heineken Dark Lagers in the Hizzy tonight....