....and if a disc fails in RAID 1,5, 10 (or any other) don't linger around
getting it fixed!
The ability to have a hot spare drive is common in high end add in
controllers and a hot spare drive is a worthwhile investment.
Chances are some time within 3 years you will need a replacement drive.
HTH
"Paul" <(E-Mail Removed)> wrote in message
news:nospam-2012052308010001@192.168.1.178..
> In article <(E-Mail Removed)>,
> "(E-Mail Removed)" <(E-Mail Removed)> wrote:
>
>> Hi All,
>>
>> I have an A8n SLI Delixe motherboard. I have 3 250GB drives.
>> Currently the drives are partitioned and my apps are on one partition.
>>
>> I want to increase how fast it takes to load the apps as I need to use
>> them. Someone suggested using RAID 0.
>>
>> I see that the controllers are built into the motherboard. I have a
>> few questions regarding this since I am new to this arena:
>>
>> 1) Should I continue to use IDE drives, or should I go with SATA?
>> 2) Is RAID 0 going to give me the increased performance, or some other
>> RAID type?
>> 3) How difficult is this to set up?
>> 4) I use Western Digital drives. If one goes bad, do I basically lose
>> the entire array?
>> 5) Can I put 4 drives in the system, and mirror the RAID 0 array to
>> have a backup at the same time?
>>
>> Thanks for any helpful input you may have.........
>>
>> Arthur
>
> 1) I was going to point you to the database at storagereview.com ,
> but they've only got SATA on there. The PATA were removed.
> The media rates for disks are still in the ~70MB/sec range
> at the beginning of the disk. It doesn't matter whether you use
> 100MB/sec PATA, 133MB/sec PATA, or 150MB/sec native SATA, the
> sustained rate is still head limited. But the newer drives will
> be packaged in SATA format, and perhaps at some point, new
> drives won't be coming out in PATA format.
>
> Faster interfaces do allow bursts of data to be held in
> cache, until the head can catch up. But, something to be
> aware of, is some caches are "multi-segmented", and not
> necessarily the entire cache can be used for one locality
> of access. I have never seen details for SATA/PATA cache
> policy, so I don't know how caches are organized on those
> disks. With SCSI disks, apparently it is possible to set up
> the cache, to do a better job in either a desktop config or
> in a server config.
>
> I/O rate is another parameter. The seek time helps determine
> the performance for random access (many small files). The
> higher RPM drives (10K SATA Raptor, 10K SCSI, 15K SCSI) have
> reduced seek time, which gives improved performance compared
> to a 7200 RPM drive.
>
> There are some potential improvements in disks. Like the
> ability for the disk to reorder seeks (tagged operation). If
> two disks have the same seek time, but one can reorder which
> read or write operation to service first, the performance of
> the drive can be improved by 10%. That improvement would be
> more visible in server environments, as in a single threaded
> situation, the application would still be waiting for the
> reordered operations to come back, and there would be a
> less pronounced improvement.
>
> SCSI has had tagged operation for many years, and SATA now
> has the option to do that as well.
>
> 2) RAID 0 is excellent for improving STR. With add-in controller
> cards, you can put eight drives in RAID 0 and get 400MB/sec.
> But then you need system busses on the motherboard that can
> handle that data rate. An example, is to stuff a PCI Express x8
> controller card, into one of the video card slots on an SLI
> motherboard (like products from Areca). Since PCI Express
> is so new, there aren't too many (cheap) choices for controller
> cards like that, so this is a more expensive option.
>
> 3) Any RAID is easy to set up. But, what people don't bother to
> experiment with, and learn about, is how to do maintenance when
> the array reports certain errors. It is important to learn how
> to repair RAID 1, RAID0+1, or RAID 5 arrays, when the RAID BIOS
> complains about the array. Simulating failures and repairing them
> will build your confidence, when facing real trouble. RAID
> manuals are generally woefully lacking in describing what to do.
> Waiting for the RAID to break, and having no backups, is the
> wrong time to be "experimenting" with the array.
>
> 4) RAID 0 is dead, when one drive fails. RAID0+1 or RAID10 are
> options with more redundancy.
>
> 5) Yes, you can do RAID0+1, and use one two disk RAID array to
> mirror a second two disk RAID array. For the cheap controllers
> built into motherboards, this is the highest performance option.
> RAID5 has pathetic write performance, and needs an expensive
> controller card with cache memory and XOR engine, to improve on
> that.
>
> You still have to do backups! Say you install four disks in a high
> performance redundant configuration. You have a smug look of
> satisfaction on your face. Then, the +12V rail on the PSU rises to
> +15V and burns the controller boards on all four disks drives. All
> your data is instantly inaccessable! There have also been cases,
> where a controller failure corrupts information on all disks, and
> that will trash the data as well. There was even one report from
> a poster, who discovered his RAID 1 mirrored array (on a SIL3112)
> was desynchronized - the two disks had different information on
> them, and yet he claims to have never had a failure report from
> the software. A redundant RAID array is not a replacement for
> backups - the main benefit is the ability to defer maintenance
> for a few hours, such as in a business environment, where the IT
> staff can fix a server array, after the employees go home.
> Redundancy there allows a server to continue to operate, when
> one disk fails.
>
> Paul