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wordwave

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Which raid volume is the fastest?

I have four 500Gb HDs and ASUS P5B-E motherboard (chipset P965 with ICH8R Southbridge Raid controller supporting Intel Matrix Storage)

I'd like to create 2 raid volumes:

1. 100Gb (Raid 10 or 0+1) for system files
2. about 1.2Tr (raid 5) for data

As I understand speed of the volume depends on part of the HD where it is phisicaly located - inner or outer. My question is: If I want to make system volume the fastest, should I create it first or after the data volume?

I will use the computer primary for multimedia editing, therefore speed and reliably are very important to me.

Thank you for your help!
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Snibborg
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The first problem you will have is that you cannot create the configuration that you have listed above with 4 disks.  You need 2 drives to create a mirrored array (RAID 1 [Redundant Array of Independent Devices]), then you need a minimum of 3 drives to create a RAID 5 array.  You cannot create different types of RAID on the same disks.

In theory, the fastest array type from the choices you are going for is that of a mirror, the next fastest is RAID 5.   My understanding is that the partitions are created from the inside out, but the difference in speed is marginal when reading and writing.  The size of the partition also affects speed of access, but is unlikely to affect performance.  Regular defragmentation is likely to have a greater benefit.

One of the best illustrations of the different RAID types can be seen here: http://www.epidauros.be/raid.jpg, just substitute hard drives for water containers.

I have recently set up RAID on a Asus Striker Extreme, but used 6 500Gb disk drives.  Be very careful that the disks you decide upon are not only the same brand but also the same model as the BIOS will reject different types, as I spent 2 days finding out :(.

I had 2 Maxtor 500 Gb and 4 Seagate 500Gb drives, the Maxtors I created as a mirror and divided into 2 partitions (200Gb operating system and 300Gb for general downloads).  The Seagates were created as a RAID 5 array giving 1.3Tb of data space, which I then divided into 3 partitions.  Because of the way that RAID 5 works, you lose the rest of the space due to data redundancy.  I have since purchased another Seagate 500Gb hard drive to use as a spare in case of failure of one of the drives in the RAID 5 array.  In a few months the model number will have changed and if there is a drive failure I'd have to replace all the drives to create a working array.  Paranoia is a terrible thing :).

Sorry if I've answered more questions than you have asked, but you question implied some misunderstandings on the way that RAID works.  Apologies if you feel it is patronising - that is not my intent.

G
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wordwave

ASKER

2 Snibborg:

Thanks a lot!

The water container illustration is simply amazing! Made my day!

So, if you are saying that "the partitions are created from the inside out", then the first one would be the slowest. Is that right?

Intel Matrix Storage does allow to create multiple raid volumes on the same set of drives. I'll divide each drive 50Gb/450Gb. The small part will go to raid 10 (making it 100Gb worth of space) and the larger part will make raid 5 volume. Then, if I want  I could create partitions on each of the volumes. I've seen this system working, so it is possible.

What I do not know is whether volumes are created the same way as  partitions (from the inside out).

I've got 4 identical WD Raid addition 2 drives with 5 years warranty. Hopefully that will do.
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RockChalk

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I would say that you are probably right with regards to the speed of rotation of the disk.  With that in mind more tracks would travel under the head in a second when reading at the outside edge than  when reading from the inside edge of the platter.  Therefore more data will be read per second.

I have to confess that I'm not exactly sure how Intel would create the volume, but logic would dictate that the same methodology would be used, as there would be little point in creating partitions from the inside out and writing data from the inside out of the partition if the underlying volume works from the outside in. if volumes were from the outside in, then the system would be sub-optimal.  Therefore volumes must follow the same method.

So create your fast volume last and put your partitions within it.  Then each platter will be reading and writing to the fastest part of the disk on the outermost edge of the platter.

Good luck with your build.

G
G
Sorry, got confused by my own logic there.  The inside section is the faster as decribed by Rockchalk.

G
Rock Chalk:

Thank you very much for your answer - great! May I ask you one more quick question? (I can post it as a new question if you'd prefer it that way.)

From your experience, how reliable my system will be (comparing with non-raid setup using the same hardware). How often do raid volumes on Intel Matrix fail?

I am basically trying to choose between 2 setups:

1. raid 10 and raid 5 using 4 HDs
2. raid 0 and raid 5 using 3 HDs + one HD for backup

Cheers!
Wordwave:

As far as how often your RAID volumes will fail, the answer to that is a combination of how likely your drives are to fail, and how the RAID level you choose will handle the single disk failure.  I may be only repeating information you already know, but RAID 5 and RAID 10 can handle a single disk failure without failing the volume.  With both of these RAID levels, if you have a single disk failure, the volume will go into a degraded state.  When degraded, your performance will drop (particularly with RAID5), but you won't loose any data.  When in degraded state, you can add a new drive (or spare) and rebuild back to full health.  If you have a RAID0 volume and one drive fails, you will loose all of your data.  Also, remember that the more drives you have in a volume, the more likely it is that one will fail.  A 4-disk RAID 0 volume will be 4 times more likely to fail than a single drive-- it will have 1/4 the reliability.  a 4-disk RAID10 volume will be far, far less likely to fail than a single drive because RAID10 provides redundancy.

As a note, Wikipedia has a pretty good article describing the different RAID levels if you're interested.

Intel Matrix Storage also will report SMART events to you for any drives that support them.  These can be indicative of a drive that's about to fail, but should not be considered a replacement for redundancy.

Given your two setups, here are the pros and cons that I see:
Option 1
Redundancy of your boot volume (a single disk failure won't cause you to loose your OS)
More space on your RAID5 volume

Option 2
Fastest performance for your OS partition

RockChalk:

Thanks again! I think I do understand the pros and cons of various raid systems, what I was asking was, from your experience how stable Intel Matrix is by itself. Or in other words, could the raid volume fail for the reasons other then failed HD? As far as I understand Intel Matrix is not pure hardware solution, so could it be that I am making my system less stable just because I am using this raid controller?

I've read pretty bad reviews (http://www.tomshardware.com/forum/216247-30-southbridge-battle-nforce-ich7-ich8#t1427805) and just wanted to ask if you've encountered similar problems.