The Raid FAQ's Thread
Okay I know a lot of folk here have a wealth of knowledge and experience with RAID, and since the demise of Icrontic I think it would be a great idea to try and once again put some of that knowledge back down onto paper (so to speak).
So in this thread post, to the point and well explained FAQ's, TIPS and INFORMATION about RAID. Whether it's to do with performance, setting up or whatever, here is the place to put it.
Let's try and keep discussion to a minumum, so this thread can be used as a easy reference and guide for RAID. Without people having to wade through tonnes of technical discussion to find the answers they want.
Cheers
So in this thread post, to the point and well explained FAQ's, TIPS and INFORMATION about RAID. Whether it's to do with performance, setting up or whatever, here is the place to put it.
Let's try and keep discussion to a minumum, so this thread can be used as a easy reference and guide for RAID. Without people having to wade through tonnes of technical discussion to find the answers they want.
Cheers
0
This discussion has been closed.
Comments
I've stickied this to encourage posts and when we have a few, Captain Spinner can edit his post to list them all up
My tips:
1) If you go RAID-0, keep regular backups. For every drive you add to an array, you increase the chances of losing all your data if it dies.
2) Don't be totally convinced that cluster size and stripe size have to match. Build it, bench it and break it down. Test it if you have the time until you find the match that work's for you.
3) Choose your controller carefully. Ask around about what is good. Don't be swayed by buzzwords and promises (pun intended) of amazing performance (especially with IDE). Ask other people's experiences and see how they find their controllers.
That's mine for now..
Here are two of the most popular latency patches:
GEORGE'S LATENCY PATCH (0.19): http://www.tec-station.com/downloads/view_download.php?id=525
GEORGE'S LATENCY PATCH INFO : http://adsl.cutw.net/dlink-dsl200-via.html
VIA'S LATENCY PATCH (1.02): http://www.viaarena.com/?PageID=66
You only need to install one of the patches
In all likely hood the patch should become redundant, but it shouldn't hurt to install it aswell (the patches after all can be uninstalled), because any changes you make in a tweaking program such as Powerstrip should simply overwrite the patches adjustments upon startup. (At least that's how I have come to understand it).
Tweaking programs such as POWERSTRIP can be used instead of the latency patches if you prefer to tweak the latency youself manually.
http://short-media.com/forum/showthread.php?s=&threadid=303
http://short-media.com/forum/showthread.php?s=&threadid=89
SCREENSHOT
RAID 0
Known as disk striping. It combines disks that are used to improve some performance, but there is no logic to protect/recover data. *Synchronized disks are used.
Pros/Cons
Fast data transfer on large blocks of data I/O. No parity check for fault-tolerance.
RAID 1
This is known as mirroring, where data is written to two different disks at the same time, and data can be read from either disk.
Pros/Cons
Secure against disk failure. Double the cost of storage.
RAID 2
Disk striping with several disks similar to RAID 0, but a small percentage of those disks were set aside to be "check disk," A special Hamming Error Correction Codes is implemented. Not used because of high performance penalty.
RAID 3
Striping data over several disks. Parity interleaves at byte level and is stored in a dedicated disk. *Synchronized disks are required.
Pros/Cons
Fastest for large-file transfer, lower cost for data security.
If the dedicated parity disk failed, all data integrity is lost.
RAID 4
Similar to RAID 3, striping data over several disks. Parity interleaves at block level rather that byte level and is stored in a dedicated parity disk. Unlike RAID 3, Non-synchronized disks are being used. RAID 4 improves read access but suffers form a write penalty since every write must access the parity disk.
RAID 5
Striping data and parity over several disks with no dedicated disk for parity.
Pros/Cons
Higher I/O rate for writing data and since no dedicated parity disks, no data loss for any disk failure Not as fast as RAID 3.
* Synchronized disks - Multiple disk are being used to write a single file. This is a function of the disk controller.
The other method of updating is only appropriate when using a plug in RAID controller card, (i.e a card which plugs into a PCI slot on your motherboard). In these situations the RAID bios will be flashed independantly to that of the motherboards BIOS, and a seperate flashing utility by the controller cards/chipsets manufacturer. e.g In the case of Highpoint a small utility called 'LOAD' is used. That can be found at the link below;
www.highpoint-tech.com/load_220701.zip
TIP
It is recommended not to flash your RAID controller BIOS to an earlier version than what it is currently using. As to do so would increase the risk greatly of you damaging any array which is currently in use.
The primary reason for combining multiple RAID architectures would be to get either a very large, or a very fast, logical disk.
The list below contains a couple of examples. It is not the limit of what can be done.
RAID 0+1
RAID Level 0+1 is the result of RAID-1 applied to a RAID-0 array/s. This will create a very fast array. If the RAID-0 controllers (hardware or software) are capable of returning an error for data requests to failed drives, then this array has all the abilities of RAID-10 See Below. If an entire RAID-0 array is disabled when one drive fails, this becomes only slightly more reliable then RAID-0.
To recover from a failed disk, it is necessary to replace the failed disk, and rebuild the entire RAID-0 array from its mirror. This requires much more disk I/O than is required to recover from a disk failure in RAID-10. It should be noted that some enterprise-level RAID controllers are capable of tracking which drives in a RAID-0 array have failed, and only rebuilding that drive. These controllers are very expensive.
RAID 1+0 (RAID 10)
RAID Level 1+0 is the result of RAID-0 applied to multiple RAID-1 arrays. This will create a very fast, stable array. In this array, it is possible to have multiple disk failures, without loosing any data, and with a minimum performance impact.
To recover from a failed disk, it is necessary to replace the failed disk, and rebuild that disk from its mirror.
RAID 5+0
RAID Level 5+0 is the result of RAID-0 applied to multiple RAID-5 arrays. This will improve the performance of a RAID-5 array, and allow multiple RAID-5 arrays to be dealt with as a single logical device. The reliability of this type of array is similar to that of a RAID-1+0 array, but it has the performance impacts of RAID-5. This type of array is most commonly found when combining multiple hardware RAID devices into a single logical device.
http://www.anandtech.com/storage/showdoc.html?i=1491
RAID, which stands for Redundant Array of Independent Disks, is in the simplest of terms, a poor mans SCSI, SCSI being currently the fastest proven form of a consumer hard disk drive. So why isn’t everyone using SCSI you ask, well it’s very expensive and doesn’t really support the capacities to warrant the extra spending. So what does that leave the average Joe with, basic, simple, bog standard IDE drives, which run through what’s called an PATA controller on a PC’s motherboard. These drives are cheap and have much larger capacities as standard, at least when compared to SCSI drives.
Now very recently a new generation of hard disk drives, which make use of a new faster type of hard disk controller known as SATA, are starting to hit the market place. At the moment the majority of these SATA drives are not much faster than their PATA standard counterparts, except the new standard carries the advantage of having a lot of room to grow. However, currently basic PATA IDE drives still offer the best value for money. So how can you get better performance out of these drives? RAID of course. RAID is a system of allowing individual hard disks to work together in a multitude of different ways and it’s worth pointing out that RAID is by no means limited to standard PATA based IDE drives, but for the purpose of this guide I will be focusing just on them.
RAID comes in many different shapes and sizes but the most popular of RAID configurations is what’s called RAID 0 (striping). Basically this allows two or more (more depending on how many channels your RAID controller has) disks to work together to create what is perceived by Windows as one disk. This newly created virtual disk which is made up of two or more drives, benefits from the combined power and speed of multiple disks working together. So essentially RAID 0 is solely for increasing the disk access performance of your system, and nothing much else.
WHAT YOU NEED
Obviously a RAID 0 array doesn’t appear out of thin air, you need the necessary components. So for practicalities sake let’s work with the assumption that you just need to set up a basic 2 disk RAID 0 array. You will need to get yourself 2 hard disks, ideally they should be the same make and model and for all intents and purposes the hard drives should both be of equal capacity. If they are not, the created array will only be the size of twice the capacity of the smallest drive. Therefore you would be wasting the added space the larger drive contains. So keep the words ‘exactly the same’ in mind when choosing drives for your RAID array.
So you’ve got yourself a pair of hard drives, what else do you need? Firstly you need a RAID controller, ideally you would want to have a motherboard with the appropriate controller onboard, but if you already have a motherboard and upgrading it really isn’t an option, the only other alternative is to buy a PCI RAID controller card. These cards simply just slot into a PCI slot (as the name suggests) and as a result adds the same functionality as an onboard controller would.
So once you’ve got all the necessary components, not to mention two high quality 80pin IDE cables (standard hard drive cables) you’re ready to start setting up the array itself.
HOW TO SET IT UP
PART I : CREATING THE ARRAY
Again, working with the assumption that you are trying to set up a two disk array, you simply need to plug each hard drive individually into each of the RAID controllers IDE sockets. In most onboard cases that would be IDE 3 and 4, and more often than not these sockets will be coloured differently to the standard IDE controllers input sockets (IDE 1 & 2). In the instance of using a PCI card controller there isn’t much to choose from. Any of the IDE sockets will do fine, and unless the number of hard disks out numbers the amount of available IDE sockets on the RAID controller, all hard disks should be on their own channel (and set to cable select). Obviously though if you are faced with a situation where you have more disks than IDE sockets, you simply slave them up to each other just like you would when using a normal IDE controller (e.g two drives on each channel, one set to master the other set to slave ; that though really depends on the controller, as in some instances having two drives both set to cable select on the same controller channel will work just fine).
Once you have the disks plugged in and powered up you are ready to start setting up the array. In the case of using an onboard controller, you need to make sure than it is enabled in the main system BIOS (you enter that in most cases by pressing delete or ESC upon system POST).
Once you have confirmed the RAID controller is enabled (figure 1, 2) you will see upon initial boot up an extra BIOS menu which should be quite obviously labelled as the RAID controller (usually specifying the controllers make and model e.g. ‘Highpoint Technologies, Inc. HPT370/372 BIOS Setting Utility v x.xx’). It should probably indicate how to enter its configuration menu, in the case of Highpoint RAID controllers CTRL-H is the key command. (Figure 3)
FIGURE 1
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/highpointenable.jpg">
FIGURE 2
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/promiseenable.jpg">
FIGURE 3
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/highpointbios.jpg">
Once you have gained access to the RAID controllers configuration menu you should see the hard disks which you have attached to the controller (Figure 4,5 ; the layout of the RAID BIOS depends on the make of the controller). If you don’t then it’s possible you haven’t attached the hard drives up properly to the RAID controller. Presuming you have and you can see them, then follow the instructions to create an array. You will need to select the drives you want to use in the array and then select the type of array you wish to create, in this case a RAID 0 (Striping) array. You may also have the option of configuring the stripe size for the array. If you are not sure of what stripe size to use I recommend using 16K. So you’ve created a RAID 0 array, what next?
FIGURE 4 (inside the Highpoint controller BIOS)
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/highpointcreate.jpg">
FIGURE 5 (inside the Promise controller BIOS)
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/promisecreate.jpg">
PART II : SETTING UP THE DISK AND WINDOWS SETUP
As far as Windows XP is concerned, it’s relatively easy from here on in. If you are setting up an array to compliment an existing installation of Windows, then when you boot Windows for the first time after creating the array then the OS should simply detect the RAID controller and prompt you (if at all) for the necessary drivers, simple as that. You will only then have to create a partition/s and format it/them using disk manager (right click My Computer – Manage – Disk Management). If though you want to install Windows onto the array itself there are a few things to do.
Firstly, you will probably need to edit the boot order (in the main system BIOS) of devices for everything to work. If your newly created RAID array is managed by an onboard controller then it will be labelled as either ‘ATA100RAID’ or ‘ATA133RAID’ or something to that effect. Which ever label it carries though it will essentially need to be set as either the first or second boot device, depending on whether or not you are initiating your XP setup from the CD drive or not. Presuming you are, then ‘CDROM’ essentially will need to be first boot and the RAID controller (‘ATA100/133RAID’) will need to be the second. Once the installation of the OS is complete you can then move the RAID controller up to first boot device as the ‘CDROM’ should no longer be needed in that role. If you are using an external controller like a RAID PCI controller card then there will be an option probably just below the boot order settings (in the main system BIOS still) labelled as ‘Boot other device’ (or something to that effect), you need to enable that option for it to look to boot from the external controller (Figure 6).
FIGURE 6
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/boot order.jpg">
Once all that is configured, the only thing you need to check now is that you have a driver disk for the RAID controller. One should have been provided by the RAID controllers’ manufacturer. Once you have that at the ready, you can now initiate the Windows XP setup program.
Almost immediately you must press F6 (when prompted) so as to instruct the setup program that you are using a third party controller (Figure 7). In this case that is the RAID controller. Later on in the installation you will be asked to provide a driver for the third party controller (Figure 8) when prompted simply insert the RAID controller driver disk that we spoke of earlier (Figure 9). If you are asked whether or not you wish to use a driver provided by Microsoft or the one on the disk you provided, I recommend you use the one provided by the manufacture, as it will more than likely be much newer than the one bundled with XP and also will be probably much better suited to your specific device.
FIGURE 7
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/f6.jpg">
FIGURE 8
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/specify.jpg">
FIGURE 9
<img src="http://www.short-media.com/files/downloads/Temp Downloads/Images/TheRAIDFaqsThread/insert disk.jpg">
All that is left to do now is create a partition (or as many partitions as you like) on the RAID array and then format it. This is pretty self explanatory during the Windows XP setup, so just follow the instructions given. When prompted though whether or not you want to quick format the partition/s, I recommend you format using the proper full format method, especially if the disks you are using are brand new.
PART III : THE FINISHING TOUCHES ; RECOMMENDATIONS
I designed this guide to be as basic as possible, so I purposefully haven’t gone into any of the advanced methods of setting up a RAID 0 array, e.g. setting up an optimal partition cluster size or anything like that. However I can offer you a few basic tips to keep your array running nicely.
RAID 0 arrays get fragmented much more easily than independent hard disk partitions, so regular de-fragmentation is necessary to maintain optimum performance. Also, after the initial installation of the OS, installing a latency patch of some sort such as the ‘VIA performance raid patch’ can greatly increase the controllers performance, though this is ultimately dependant on what RAID controller and motherboard chipset you are using.
RAID 0 is a great way of increasing the overall desktop performance of your PC. Think about that before you next upgrade your system. I hope this guide proves to be helpful.
Written by Jon Scott (SPINNER)
My RAID Died http://www.short-media.com/forum/showthread.php?s=&threadid=219
SCSI Raid http://www.short-media.com/forum/showthread.php?s=&threadid=304
Bestest Raid Card http://www.short-media.com/forum/showthread.php?s=&threadid=725
RAID 0 with 4 disks http://www.short-media.com/forum/showthread.php?s=&threadid=303
Here´s a couple of Raptor Raid 0 scores http://www.short-media.com/forum/showthread.php?s=&threadid=799
Need Help with my Highpoint Raid http://www.short-media.com/forum/showthread.php?s=&threadid=3794&highlight=raid
Promise TX4 vs Silicon Image http://www.short-media.com/forum/showthread.php?s=&threadid=3878&highlight=raid
Setting up RAID http://www.short-media.com/forum/showthread.php?s=&threadid=3775&highlight=raid
RAID disks? http://www.short-media.com/forum/showthread.php?s=&threadid=3636&highlight=raid
ATTO on RAID-0 http://www.short-media.com/forum/showthread.php?s=&threadid=3144&highlight=raid
RAID question http://www.short-media.com/forum/showthread.php?s=&threadid=3087&highlight=raid
Cheapest Raid 1 card? http://www.short-media.com/forum/showthread.php?s=&threadid=2642&highlight=raid
RAID 0 ATA assistence http://www.short-media.com/forum/showthread.php?s=&threadid=2866&highlight=raid
I need SATA and PATA Raid controller cards! http://www.short-media.com/forum/showthread.php?s=&threadid=2464&highlight=raid
RAID http://www.short-media.com/forum/showthread.php?s=&threadid=2236&highlight=raid
RAID 5 or RAID 0+1 and other questions... http://www.short-media.com/forum/showthread.php?s=&threadid=1867&highlight=raid
IDE-SATA Adaptors http://www.short-media.com/forum/showthread.php?s=&threadid=1174&highlight=raid
Anyone interested in a scsi raid controller cheap? http://www.short-media.com/forum/showthread.php?s=&threadid=1774&highlight=raid
Performance boost?? http://www.short-media.com/forum/showthread.php?s=&threadid=932&highlight=raid
http://fdisk.radified.com/
http://partition.radified.com/
Yes there is. Your RAID controller will need to support this mode however.
SPANNING (JBOD) (2-4 disks required)
1. Select the "Create RAID" selection from the main menu
2. Select "Spanning (JBOD)" in the "Array Mode" pop-up menu
3. Select the disk drives to be used with the "Select Disk Drives" selection
4. Select the "Start Creation Process" selection
A JBOD array stands for "Just-a-Bunch-Of-Disks" which basically takes both drives plugged into that particular Raid port and combines them into one logical drive with however much storage space you have on both drives combined.
I am 99% sure the HPT374 chip which is on that motherboard supports it.
"Most folks used to get the best all around results with 16 stripe/16 cluster. With the advent of newer controllers and different HD's there has been some experimenting to what works best in someones particular system. I myself found that both of my arrays with WD SE drives prefer to be run with a stripe size of 32. My array with 2 WD1000JB HD's in RAID-0 on a HPT 1520 controller like a cluster size of 8 so it is 32/8. My array with 2 WD 60JB HD's in RAID-0 on the onboard Silicon Image controller like a cluster size of 16 so it is 32/16. I have another computer with 2 Maxtor HD's in RAID-0 on an onboard HPT 372 controller that just loves 16/16 and coughs at most other configs. I recomend experimenting with all the different combinations you can. I like to start at 16/16 and try all the different clusters on thae 16 stripe; ie 16/16, 16/8, 16/4. Then I go with 32/32, 32/16, 32/8, 32/4. Then try 64/64, 64/32, 64/16, 64/8. The larger the cluster size the more disk space you will use and won't be as space efficient. I didn't mention using less that 16 stripe as it uses more processor useage so as not to be as high of performance. I also never use a cluster more than 1/4th my stripe size as it won't do any good. It is important to do a full format when changing sizes. DO NOT USE THE "QUICK FORMAT" OPTION. When running ATTO I like to average the results of at least 5 runs and make sure you have nothing else open.
The next thing after you find a stripe/cluster with the best level of performance is to adjust the PCI Latency of your controller. For this I use A tool called Powerstrip. Once you have it installed you will need to open it, which puts an icon in your toolbar. Right click the icon go to: Options>Adapter Information.
Next you need to:
1. Scroll through the device list till you find your controller.
2. Uncheck the box marked "Read Only".
3. Adjust your latency. Try everything between 32 and 248.
Here is an array prior to latency tweeking:
Here is the same after:
In a word, no. If you have a hard disk you wish to use in conjunction with another to create a RAID array, any data on either of the disks will be lost. So if you wish to retain that information, you will need to back it up to another storage medium, then transfer it onto the array once it has been created.
http://www.madshrimps.be/gotofaqlink.php?linkid=111
http://www.soyo.com.tw/kb/kbdesc.php?id=205
http://publib16.boulder.ibm.com/pseries/en_US/aixbman/prftungd/2365c818.htm
http://www.buildorbuy.net/raid.html
http://www.pctechguide.com/tutorials/RAID.htm
http://www.techtutorials.info/hwraid.html
http://www.techtutorials.com/tutorials/hardware/raid.shtml
http://www.acnc.com/04_00.html
http://www.anandtech.com/storage/showdoc.html?i=1491&p=2
http://www.computerhope.com/help/raid.htm
http://www.storagereview.com/guide2000/ref/hdd/perf/raid/levels/singleLevel0.html
http://www.tweakhardware.com/raid/
http://www.pcguide.com/ref/hdd/perf/raid/levels/single-c.html
http://searchstorage.techtarget.com/originalContent/0,289142,sid5_gci939868,00.html
http://tech-report.com/reviews/2002q4/ideraid/index.x?pg=1
http://www.itstorage.co.uk/default.asp?page=/Resources/WhitePapers/item_list.asp
http://www.arstechnica.com/paedia/r/raid-1.html
http://www.viaarena.com/?PageID=80
http://www.recoverdata.com/raidfaq.htm
http://www.buildorbuy.net/raid.html
http://www.acnc.com/04_01_00.html
http://www.raidtoolbox.com/raidinfo.html
http://www.tutorgig.com/searchtgig.jsp?keywords=Ide+Raid
http://www.dalantech.com/boards/showflat-Cat--Number-31868-page-0-view-collapsed-sb-5-o--fpart-1.html
http://www.geocities.com/SouthBeach/Canal/8593/raid/misc03.htm
http://support.premiopc.com/faqs/raid.htm
http://www.gen-x-pc.com/more_raid.htm
http://faq.storagereview.com/
http://www.uni-mainz.de/~neuffer/scsi/what_is_raid.html
http://www.sms.com/raid_tut.htm
For more detailed information on RAID levels you can visit The PC Guide Single RAID Levels and Multiple (Nested) RAID Levels. There is also a HUGE RAID glossary on the Adaptec website that I would recommend looking over as well. The Adaptec site also has a decent section on the difference between Hardware and Software RAID designs.
Thanks to Automaton for all these.
The latest Windows OS, Windows XP, has this ability (not the HOME version), as do a handful of other Windows and non-Windows based OS's.
The primary draw back of using a Software RAID setup is that you can't run an OS on a software RAID partition, simply because the OS or software has to be loaded first so it can initialise the array. It's essentially the chicken and the egg scenario. Make note though that I said partition, not drive. As long as your OS is on a separate partition, another partition on that very same hard drive can be used to help make up a striped array (RAID-0). For RAID-1 however, you will require 3 hard drives in total. This is because Windows will not let you perform any volume operations on a boot disk or a swap disk.
Below are some related FAQ's:
Windows XP Pro supports RAID-0, RAID-1 and RAID-5 as well as spanning.
You need at least two dynamic disks to create a striped array (RAID-0) and at least three if you wish to setup a mirror array (RAID-1).
You must be logged on as an administrator or be a member of the administrators group in order setup software RAID under Windows.
Unlike in a hardware RAID environment, there is no need for matched drives.