?
Solved

Raid

Posted on 2003-03-07
23
Medium Priority
?
1,534 Views
Last Modified: 2016-12-08
What is better Raid 5 or Raid 10?
0
Comment
Question by:elegal
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 7
  • 6
  • 5
  • +5
23 Comments
 
LVL 56

Expert Comment

by:andyalder
ID: 8089663
Raid 10 (0 + 1) is faster and as long as mirror before stripe has got some chance of surviving a two drive failure; raid 5 is cheaper.
0
 
LVL 22

Expert Comment

by:Christopher McKay
ID: 8089700
Raid Level 10 is better, see this page for Raid level descriptions:
http://www.sqlmag.com/Articles/Index.cfm?ArticleID=9697

Hope this helps!

:o)

Bartender_1
0
 
LVL 4

Expert Comment

by:pratigan
ID: 8089788
Also, depending upon your usage of either a card or motherboard configuration.
Those cards shave at best a couple percentage points off cpu usage. They offer nothing over onboard controllers, or software raid cards in terms of performance. Today's gigihertz+ cpus offer way better performance than the processors used on raid cards. What reviews I have have all shown best performance with software raid controllers. What those cards have are additional raid support, such as raid 5. Riad 5, however, offers no performance whatsoever. Rather, it greatly impedes performance. Very few, none to be sure, home users have any need to use raid 5. Very few do, I am sure, since most people purchase raid for performance, not redundancy, and use raid 0.Depends on what you are looking for. As an example my embedded Scsi Raid card was designed for Raid5. So when i use it for Raid10, performance s***s bigtime. Hardware RAID cards are really only good for one thing: RAID 5 configurations.

I guess it really depends upon what you are lookinig to gain.  Let me know if this helps.. I do have much more information regarding RAID comparisons.
:)
Paul

0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 56

Expert Comment

by:andyalder
ID: 8089962
>Hardware RAID cards are really only good for one thing: RAID 5 configurations.

I think you're talking about the toy raid controllers that pretend to do hardware raid but do most of it in the driver. If you have 256MB of battery backed cache and 4 scsi channels on the controller it should speed up performance no end.
0
 

Author Comment

by:elegal
ID: 8090379
Expensive is not an issue, but reliability and performance are keys issue.
0
 
LVL 56

Expert Comment

by:andyalder
ID: 8090918
If expense is not an issue then as many drives and shelves as you can afford, mirroring the same data many times means there are more heads available to be near to the track where your data is, the smaller capacity the disks are the better the performance but the more of them you have to buy.

Offload the bulk storage onto a hetrogenious SAN and duplicate the same SAN on a remote site so as to be available for DR, keep log disks local and mirrored with battery backed cache since you can do without their data at a scrape.

That's close to a million bucks but it will give you access to your data at gigabit speed and 5 nines on relyability. Just how much data and how fast do you want to get at it for a ballpark figure?
0
 
LVL 8

Expert Comment

by:heskyttberg
ID: 8095778
Hi!

Just commenting some false statements:
>Those cards shave at best a couple percentage points off cpu usage. They offer nothing over onboard controllers, or software raid cards in terms of performance.

True for IDE raid cards which arent really RAID except for maybe some of the more expensive adaptec cards.

>Today's gigihertz+ cpus offer way better performance than the processors used on raid cards. What reviews I have have all shown best performance with software raid controllers.

Yes, software raid is faster, but it might take 30-50% of your CPU cpacity something very unwanted on DB and APP servers. A real SCSI raid will oofload the CPU ver very much, I sense you have never ever come in contact with or used SCSI, even a cheap scsi card and scsi disk offloads CPU more than IDE which uses CPU heavily even locking system at times. Ask anyone about putting CD into a IDE compared to a SCSI one.

>What those cards have are additional raid support, such as raid 5. Riad 5, however, offers no performance whatsoever. Rather, it greatly impedes performance.

So wrong again RAID 5 gives a perfomance bost as well as redundancy. Each raid cahnnel on a Utra SCSI-3 controller can shuffle 80Mb/sec. Each independent drive can move something like 8-10Mb/sec. We use two channels, 10 drives on each doing one big RAID 5. You will see disk transfer rates the IDE would never even be able to dream of allthough IDE should beat that scsi card in theory, it has no chance, like comparing a fiesta with a ferrari. This setup would almost max out both channels giving you about 140Mb/sec transfre rate. I'm still waiting for any IDE setup to reach such numbers.

>Very few, none to be sure, home users have any need to use raid 5. Very few do, I am sure, since most people purchase raid for performance, not redundancy, and use raid 0.

This is true for you and many others buying a mobo with onboard RAID, but so untrue for most using raid, companies. Their main reason for RAID is redundancy not performance. Performance is just a side gain, redundancy is much more important. That's why clustered server requiring 99.9% uptime often have two raid cards crosslinked to two mirrored external disk arrays.


It's true that by buying the right IDE HDs you can get the same performance from two IDE drives as from two SCSI HDs, but the SCSI hds won't lock your system as much. With SCSI you would be able to play games, convert a movie from avi->mpeg, run a ftp server and burn a CD at the same time. This I wouldn't dare doing on a IDE system raid or no raid.

Regards
/Hans - Erik Skyttberg
0
 
LVL 8

Expert Comment

by:heskyttberg
ID: 8095789
Hi!

I explained the SCSI standards once before so for anyone interested:
http://www.experts-exchange.com/Hardware/Q_20525260.html

Regards
/Hans - Erik Skyttberg
0
 
LVL 7

Expert Comment

by:kohashi
ID: 8096662
That was quite an interesting read.  Heskyttberg:  thats why I would use one sstem for burning, one for converting, one as a server and one as a gaming machine :)

-kohashi
0
 
LVL 56

Expert Comment

by:andyalder
ID: 8097198
>Their main reason for RAID is redundancy not performance.

Main reason for raid 5 is redundancy, but raid 0+1 can be more about speed, that's why DEC ^H^H^H Compaq ^H^H^H^H^H^H HP allow 6 mirrors of the same data with the HSx80.

This one might amuse you Hans - Eric, SQL server spec from Microsoft, 4 channel raid card, 2 mirrored OS boot on bus0, 2 mirrored swap on bus0, mirrored logs on bus1, 6 in raid 10 for data on bus2 and 6 in raid 5 on bus3 for reports, all 18GB 15K drives. Now why have each array on it's own channel rather than spread them evenly across the channels? I would have split each across as many channels as was available, what about you?
0
 
LVL 8

Expert Comment

by:heskyttberg
ID: 8097329
Hi!

Yes, very true, I would also have spread them evenly on the buses, since the bus with 6 discs might outperform the total bus speed so you won't get the full potential.

A reason not doing it might be because of where the discs are located.

Thoose on bus 0 and 1 is probably in the server, while the ones on bus 2 and 3 might be in external cases, so not much to choose from.

Raid 0+1 will only make a BIG speed difference over raid5 if the controller can do reads from all mirrors.
Not all controllers can do that and what you might gain in speed you loose in the mirroring since the controllers CPU needs to do two calculations 'so to speak' instead of one.

Regards
/Hans - Erik Skyttberg
0
 

Author Comment

by:elegal
ID: 8103394
I have worked with Raid levels 0,1,and 5(software and hardware controllers. All of this stems from a disagreement with another engineer. We have a client who has been running an IBM 36 Mainframe server for the last several years, and is forced to use and Intel based solutions. The client cannot afford downtime so I suggested that we use a Raid controllers with Raid 5 configuration, but another enginner disagress with me stating we should implement Raid 10. Thats the bottem line
0
 

Author Comment

by:elegal
ID: 8103473
I have worked with Raid levels 0,1,and 5(software and hardware controllers. All of this stems from a disagreement with another engineer. We have a client who has been running an IBM 36 Mainframe server for the last several years, and is forced to use and Intel based solutions. The client cannot afford downtime so I suggested that we use a Raid controllers with Raid 5 configuration, but another enginner disagress with me stating we should implement Raid 10. Thats the bottem line
0
 
LVL 56

Expert Comment

by:andyalder
ID: 8103529
IBM System 36 was a mini rather than a mainframe but it must be over 15 years old! Apply Moore's law, a single IDE disk is probably faster and more relyable that any number of 14" Winchesters.
0
 

Author Comment

by:elegal
ID: 8103677
I have worked with Raid levels 0,1,and 5(software and hardware controllers. All of this stems from a disagreement with another engineer. We have a client who has been running an IBM 36 Mainframe server for the last several years, and is forced to use and Intel based solutions. The client cannot afford downtime so I suggested that we use a Raid controllers with Raid 5 configuration, but another enginner disagress with me stating we should implement Raid 10. Thats the bottem line
0
 

Author Comment

by:elegal
ID: 8103793
I have worked with Raid levels 0,1,and 5(software and hardware controllers. All of this stems from a disagreement with another engineer. We have a client who has been running an IBM 36 Mainframe server for the last several years, and is forced to use and Intel based solutions. The client cannot afford downtime so I suggested that we use a Raid controllers with Raid 5 configuration, but another enginner disagress with me stating we should implement Raid 10. Thats the bottem line
0
 
LVL 34

Expert Comment

by:arbert
ID: 8106057
Remember for each logical write on RAID5, the disks actually have to perform 4physical writes.  RAID5 is slow and is hit with a penalty when you are doing lots of writes.  However, RAID5 does offer good read performance.

Raid0+1 (10) on the other hand, only has to do 2physical writes for each logical write and is far superior for applications that do lots of writes.

A person can't simply say RAID10 or RAID5 is the best--depends on the application and the environment.

Brett
0
 
LVL 8

Expert Comment

by:heskyttberg
ID: 8107125
Hi!

Raid 5 is increased performance + redundancy.
Raid 0 is pure performance, lose one disk and all data is gone.
Raid 1+0, this will most likley need really good raid controllers to give much boost over radi5.

arbert, the number of writes is dependant on how many drives you have. A 10 disk raid 5 will most likely outperform a raid 1+0 setup with 10 disks.
So to get faster you would need 20 drives for the raid1+0.
I agree that it is very dependant on what you intend to use it for. If data isn't sensitive to hd crash the optimum would be a 10 disk raid0. In SCSI systems multiple read/writes is a positive thing that you want.

As stated in another post above, a raid 5 with 10 9Gb drives will be quicker than one with 5 18Gb drives. This might not apply to IDE though, I have not much experience with IDE raid, but my opinon on thoose is they are good enough for home use, but I wouldn't use it in a production environment. That has not anything to do with transfer rates, some of todays IDE drives are quick enough, but not as ralialbe or tolerant as SCSI.

Regards
/Hans - Erik Skyttberg
0
 

Author Comment

by:elegal
ID: 8111514
The server is goimg to be there bread and butter so disk failure is unacceptable.
0
 
LVL 8

Accepted Solution

by:
heskyttberg earned 200 total points
ID: 8111724
Hi!

For a system where no downtime is more important then HD speed, you might consider something like the following.

Clusterd servers, each with two scsi controllers.
Two external cabinets to wich both servers are connected.
The external cabinets both run RAID5 and are mirrored to each other. This will cost a bunch but 4 drives needs to fail at the same time, two in each cabinet in order for the need fo tape restore and for cluster to become unavailible either both computers need to fail at same time or all four scsi controllers. Any of theese scenarios is very unlikely to happen.

Or just a little safer you might even consider raid1+5 instead of 1+0.

If money is no object I would as suggested above recommend some sort of SAN and fibre channel.

Regards
/Hans - Erik Skyttberg
0
 

Expert Comment

by:Gurru
ID: 8137994
I build and configure file servers.
SCSI, IDE, SATA and Fibre Channel.
I agree with "heskyttberq" 100% His facts are straight!
Some of you out them talk about things you don't really know. Just because you use something does not make you experts! Make sure your facts are correct. Don't state your opinions as facts, Please!

I recommend...
http://www.3ware.com/products/
The Escalade™ 8500 Series offer better performance than SCSI RAIDs. Redundancy & cost effective.
With this you can use IDE disks with the SATA adaptor.
It does not take a performance hit like SCSI & IDE RAIDs.
Each disk has its own cable.
If cost is not a consern use Fibre Channel
0
 

Author Comment

by:elegal
ID: 8140761
I would like to thank everyone.
0
 
LVL 56

Expert Comment

by:andyalder
ID: 8143276
Q> which is better, raid 10 or raid 5
A> a cluster.

What a joke. Next question is probably going to be what is taller, empire state building or canary wharf tower and the answer will be Mount Everest.
0

Featured Post

Microsoft Certification Exam 74-409

Veeam® is happy to provide the Microsoft community with a study guide prepared by MVP and MCT, Orin Thomas. This guide will take you through each of the exam objectives, helping you to prepare for and pass the examination.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Create your own, high-performance VM backup appliance by installing NAKIVO Backup & Replication directly onto a Synology NAS!
A look at what happened in the Verizon cloud breach.
This video teaches viewers how to encrypt an external drive that requires a password to read and edit the drive. All tasks are done in Disk Utility. Plug in the external drive you wish to encrypt: Make sure all previous data on the drive has been …
This Micro Tutorial will teach you how to reformat your flash drive. Sometimes your flash drive may have issues carrying files so this will completely restore it to manufacturing settings. Make sure to backup all files before reformatting. This w…
Suggested Courses

762 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question