RAID: Mode 0 or Mode 1?

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[ARCHIVED THREAD] - RAID: Mode 0 or Mode 1?

Posted: 9/7/2004 7:42:21 PM EDT

After six months of running my pleasure machine in Mode 0, I must say that I'm pleased. It's very fast and has been bullet-proof reliable.

I'm thinking about building another mission-critical work computer featuring Mode 1 for redundancy.

What say you?

Posted: 9/7/2004 7:43:15 PM EDT

[#1]

RAID 0 is anything but reliable. fast yes, reliable nope. If you can't RIAD 5, Don't RAID

Posted: 9/7/2004 7:46:29 PM EDT

[#2]

RAID 0 (Striping) is just asking for trouble. A drive WILL fail and when it does the file system on both drives is toast. Data's gone. RAID 1 is good, just not very space effiecient.

Posted: 9/7/2004 7:46:30 PM EDT

[#3]

I'd say it depends on what your using it for. Read up here:www.storagereview.com/. For most users, raid doesn't really offer much benifit and in many cases just running WD Raptors is faster (10,000rpm).

Posted: 9/7/2004 7:47:19 PM EDT

[#4]

I thought a RAID was an assualt pack??

Posted: 9/7/2004 7:53:57 PM EDT

[#5]

RAID 0 isn't redundant and it fact it halfs the mean time between failures

RAID 1 is mirroring and is the least effecient level of RAID - only 50% effecient.

As others have mentioned RAID 5 is sweet but it takes at least 3 drives.

Posted: 9/12/2004 1:12:33 PM EDT

[#6]

Quoted:
RAID 0 (Striping) is just asking for trouble. A drive WILL fail and when it does the file system on both drives is toast. Data's gone. RAID 1 is good, just not very space effiecient.

Yes BTDT

....0 is faster, but save for something that will not cause you "real life" disruption if you lose it (and the best hdd will fail for any number of reasons) like online gaming or home video editing.

For what is now probably about 50 cents a gigabyte, buy 5 drives and go with RAID 0+1 with a hot spare.... Check the sales and promos....ATA133 drive prices are plummeting!

edited to change "raid 5" to "raid 0+1" because Digdug reminded me of what I MEANT to say.

Posted: 9/12/2004 1:21:15 PM EDT

[#7]

Raid 5 or go home. Just as good a redundancy as 1 (to most users) and it doesn't have the same storage size drawbacks 1 has.

Posted: 9/12/2004 1:24:45 PM EDT

[#8]

OK people, here is the lesson for the day.

Raid 0: Data striping across multiple drives. Fast but if a drive blows you lose all data in data set.

Raid 1: Data Mirroring. Two hold a given amount of data, you need double the drives, but every bit is written to both drive. Very reliable, fast (faster than raid 5, slower then RAID 0) but more $$$$. Double the drives.

Raid 2-4: Beyond the scope of this discussion.

Raid 5: Must use at least 3 drives. Data is written and then parity information is written to an additional drive so if a drive fails the system can still run and reconstruct data when the failed drive is replaced. Read speed is fast, but writes are slower than raid 1. If you do a lot of reading from the data set but not much writing, Raid 5 works well. Cached raid controllers can help increase write speeds to some extent.

If you need the ultimate in speed and reliability, use RAID 0+1. You get the benefits of striping (speed) and the write speed of mirroring. You can have multiple drive failures also. It is the most expensive option, but if you need the read AND write speed it is the best option.

Posted: 9/12/2004 1:25:40 PM EDT

[#9]

Quoted:
Raid 5 or go home. Just as good a redundancy as 1 (to most users) and it doesn't have the same storage size drawbacks 1 has.

But has write speed issues and has issues with multiple drive failures.

Posted: 9/19/2004 10:20:34 PM EDT

[#10]

what is the machine going to be used for?

Posted: 9/19/2004 11:05:58 PM EDT

[#11]

I love RAID 0, live fast die fast download it all again. I stopped loving data when I came home with 2 100 gig drives to throw in with the other 2 for RAID 0+1, and heard one of them clacking away. The loss of 180 gigs will leave you looking for things you will never find, for months.

Mike

Posted: 9/19/2004 11:34:20 PM EDT

[#12]

+1 0+1

My new units will be RAID 0 backed up to NAS

ETA , or you could use a RAID 10 or 50 server setup if your funds are large

Posted: 9/20/2004 12:42:50 AM EDT

[#13]

Chrome1 - what sort of NAS are you hooking up? And where in NY are you?

Posted: 9/20/2004 1:12:44 AM EDT

[#14]

Quoted:
Chrome1 - what sort of NAS are you hooking up? And where in NY are you?

This is the one I'm looking at NAS
I'm in the lower Hudson Valley , close to Fishkill .

Posted: 9/20/2004 9:11:45 AM EDT

[#15]

judging by what you have shown us, you are dropping some good $$ on this equiptment. have you ever thought of going scsi raid? even the 10krpm u160 scsi devices are just as fast as todays 7200, 8MB cache drives and pretty close to the raptors, the 15krpm u320 drives eat the raptors for lunch.

my main drive is a single (looking for a deal on a u160/u320 raid card) 10k rpm u320 scsi drive and i must say it is pretty quick. now, combine that with a raid card where you can easily add 7 or more drives in a striping/mirroring arrangement you are set.

Posted: 9/20/2004 9:28:07 AM EDT

[#16]

RAID 0, lose twice the data twice as fast!

RAID 50 looks interesting but I haven't seen much real world feedback on it.

Posted: 9/25/2004 12:14:00 PM EDT

[#17]

RAID0 is not as fragile as many here have made it out to be; especially with the better quality drives available. You generally have fair warning when something is about to let go. That said, I don't run anything I want to keep on my RAID0 drives.

RAID0 and RAID1 can be implemented in software-based controllers fairly easily, and at fairly low CPU usage as compared to a single drive.

RAID5 is another beast entirely. There are software based-RAID5 controllers but they are horribly slow and VERY CPU-intensive. Hardware RAID5 controllers are not cheap. $200+ for one, but they do run like stink from a skunk. RAID5 arrays require much more overhead both in drives nd hardware, and if a RAID5 card goes south, you could be in for a rude awakening in trying to retrieve your data.

For most users looking to create a Fileserver/NAS/SAN solution, RAID1 is probably the safest, simplest choice. The only drawback is that it is not very space-efficient. But with drive prices the way they are, who cares?

This is coming from a guy who is running his fileserver from a RAID5 array. I will be switching to a RAID1 array as soon as practical; I will be purchasing a pair of 250GB Drives for the task. Why? It's cheaper than running six 80GB Drives in RAID5, and uses one hell of a lot less power.

Posted: 9/30/2004 6:28:30 PM EDT

[#18]

Quoted:
RAID5 is another beast entirely. There are software based-RAID5 controllers but they are horribly slow and VERY CPU-intensive. Hardware RAID5 controllers are not cheap. $200+ for one, but they do run like stink from a skunk. RAID5 arrays require much more overhead both in drives nd hardware, and if a RAID5 card goes south, you could be in for a rude awakening in trying to retrieve your data.

Abjectly wrong statement. Perhaps on a shitty controller. But any true hardware RAID card, like an HP SMART card you just replace the card, rebuild the array from the ACU and your up and running again.

Posted: 10/2/2004 1:59:17 PM EDT

[#19]

Abjectly wrong statement. Perhaps on a shitty controller. But any true hardware RAID card, like an HP SMART card you just replace the card, rebuild the array from the ACU and your up and running again.

This is true on paper, but I have been through enough disaster recoveries to know that more than one RAID card has taken a filesystem or two down with it. It is by no means common, but it does account for about 5-8% of the DRs I have worked on as far as "Root Cause" is concerned, the bulk of the rest being multiple drive failures.

Perhaps it would be better if clarified my previous statement: Make sure you have a RAID card with good support (i.e. replaceable), running an old RAID card that is no longer manufactured/supported can cause problems on down the road.

Posted: 10/6/2004 12:01:57 PM EDT

[#20]

Ok, guys, I run a large county government network complete with 40+ servers, a 1.4TB SAN, and lotsa other goodies. Quick and dirty on RAID:

RAID 0 = you really do not get much speed increase. Damn sure lose reliability
RAID 1 = More reliable, not space efficient. We use this on servers where we use the drives just to load the OS and store the data on the SAN.
RAID 5 = provided it is a stable hardware-based solution, this is the shizznit. If set up properly, it can take multiple drive failures, and recover on the fly with ease. I regularly pull bad HDDs out of RAID arrays in production servers, slap in the new one, and keep right on trucking. Too damn expensive for most home users.

Honestly, for a home user, skip the RAID bullshit and just get some good fast drives and make regular backups.

Posted: 10/6/2004 8:57:47 PM EDT

[#21]

Ok, guys, I run a large county government network complete with 40+ servers, a 1.4TB SAN, and lotsa other goodies. Quick and dirty on RAID: ...

Only 40?

RAID 5 = provided it is a stable hardware-based solution, this is the shizznit. If set up properly, it can take multiple drive failures, and recover on the fly with ease. I regularly pull bad HDDs out of RAID arrays in production servers, slap in the new one, and keep right on trucking. Too damn expensive for most home users.

You lose two drives out of a RAID 5 set and you are hosed. One failure is the limit per set. Now, if you have two mirrored RAID 5 arrays, you could sustain a two drive failure, but the drives would have to be in different mirrored sets.

It doesn't matter if there are 3 drives or 15 drives in the set, if you lose more than one drive from the set, you will have lost parity and the array. The law of averages actually puts a HIGHER failure rate on RAID5 arrays constituted from larger drive pools, simply because there are more points of failure. But the flip side to this is any one failure should be recoverable.

Three drive arrays are the most reliable from a hardware failure standpoint, but best performance is found with more drives. Most manufacturers stop at 6 drives with RAID5 arrays (5 drives + 1 hotspare) to balance performance with reliablity and rackspace.

Posted: 10/20/2004 11:28:17 AM EDT

[#22]

Raid 5: Must use at least 3 drives. Data is written and then parity information is written to an additional drive so if a drive fails the system can still run and reconstruct data when the failed drive is replaced. Read speed is fast, but writes are slower than raid 1. If you do a lot of reading from the data set but not much writing, Raid 5 works well. Cached raid controllers can help increase write speeds to some extent.

Close. What you describe is actually RAID level 4. RAID level 5 distributes the parity stripe across the array instead of putting it all on one drive. It's faster because reads & writes do not bottleneck on a single drive when storing parity information.

Posted: 10/20/2004 4:33:13 PM EDT

[#23]

Raid 1 on system drives, Raid 5 on data drives. Go big or go home...IDE Raid cards and drives are dirt cheap. Don't scrimp or you'll be crying when you get that error message on boot "OS Not found"

Posted: 10/20/2004 4:37:46 PM EDT

[#24]

Man there is a TON of misinformation/incomplete info in this thread!

Posted: 10/20/2004 4:46:06 PM EDT

[#25]

I ran (and still run) RAID 0 (one pair on a hardware controller, one using Windows XP.) It's smoking fast, but I had a drive go bad, and it was a PITA to replace. When I build the next computer, I'll get a good card that can do RAID 5.

Posted: 10/20/2004 5:06:52 PM EDT

[#26]

0 + 1 for me

for one thing, the extra drive is only 100 more bux

secondly, most mobos with integrated sata raid only support 0, 1 and 0 + 1, and NOT raid 5

i'd prolly go 5 if there was a good on-mobo solution for raid 5 available

Posted: 10/20/2004 7:15:56 PM EDT

[#27]

Quoted:
0 + 1 for me

for one thing, the extra drive is only 100 more bux

secondly, most mobos with integrated sata raid only support 0, 1 and 0 + 1, and NOT raid 5

i'd prolly go 5 if there was a good on-mobo solution for raid 5 available

For my next setup, I'm definitely going with a plug-in controller. I really don't want to deal with losing the controller and having to get a new mobo to get the array working.

Posted: 10/20/2004 7:31:48 PM EDT

[#28]

Quoted:
Quoted:
0 + 1 for me

for one thing, the extra drive is only 100 more bux

secondly, most mobos with integrated sata raid only support 0, 1 and 0 + 1, and NOT raid 5

i'd prolly go 5 if there was a good on-mobo solution for raid 5 available

For my next setup, I'm definitely going with a plug-in controller. I really don't want to deal with losing the controller and having to get a new mobo to get the array working.

well, in my case, if the mobo goes down... i gotta get a new one anyway!!!

Posted: 10/21/2004 1:14:13 AM EDT

[#29]

Quoted:
0 + 1 for me

for one thing, the extra drive is only 100 more bux

secondly, most mobos with integrated sata raid only support 0, 1 and 0 + 1, and NOT raid 5

i'd prolly go 5 if there was a good on-mobo solution for raid 5 available

My latest build is on an ASUS K8N-E for Athlon 64. Contains both an nVidea 2 channel SATA bus (supporting 0, 1, 0+1) AND a Silicon Ind. 4 channel array that includes 5.

Interesting Mb..it also contains a native on-board firewall

and a dizzying array for "admin" features.....I think the damn thing must have been designed by an ex-sysop.

Also, found a great place with good prices on components and BARE miniboxes for those interested in doing an external RAID.

Looky here --->www.caloptic.com/

Posted: 10/22/2004 9:57:08 AM EDT

[#30]

Quoted:
0 + 1 for me

for one thing, the extra drive is only 100 more bux

secondly, most mobos with integrated sata raid only support 0, 1 and 0 + 1, and NOT raid 5

I'd problly go 5 if there was a good on-mobo solution for raid 5 available

Intel is making one.. the ICH6?
If memory serves.. it will have raid5 ability for SATA drives.

Posted: 10/26/2004 6:09:59 AM EDT

[#31]

Intel's ICH5R and ICH6R are RAID-capable (ICH5R can do RAID 0 or 1, ICH6R can do RAID 0+1 as well).

Again, I was describing RAID5's Parity strategy.

RAID4 works like a primitive RAID5 array the prime differences being the use of a dedicated Parity drive (if that drive falls to pieces you can stop the array and rebuild the parity drive, or if you lose a single storage drive, you can similarly restore it as well with the parity information; you cannot rebuild on the fly like you can with RAID5.

RAID4 has it's uses in low-latency high volume data writes (Realtime Audio and Video). You need at least three logical or physical drives to run a RAID4 Array. This is one of the rarest RAID arrangements still used today.

[ARCHIVED THREAD] - RAID: Mode 0 or Mode 1?

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