Anyone explain RAID?

By henrychieng · 115 replies
Mar 12, 2002
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  1. alphnumeric

    alphnumeric TS Rookie Posts: 173

  2. MESS

    MESS TS Rookie

    That was exactly what I was looking for I have an external hard drive which I use to store important information and anything that is super important I stick on a DVD anyway. Raid 0 sounds like what I am looking for. Next question. Is the system that I bought going to work, unfortunetly I have not even seen it yet and will not for another couple of months. I just want to make sure that I have everything that I need to make it work when it shows up.

    Video card: Radeon 9600 128m

    Motherboard and Processor: Asus A8V Deluxe Via Socket 939 ATX Motherboard and AMD Athlon 64 3400+ Processor
    (built in 5.1 dobey digit sound)

    Memory: Ultra 512MB PC3200 DDR 400MHz Memory
    2 sticks

    Hard Drives: Western Digital / Caviar SE / 120GB / 7200 / 8MB / SATA-150 / Hard Drive
    2 identical ones

    Case: EZ-Media G7 Black ATX Mid-Tower Case with Clear Side, Front USB Ports, Front Thermo LCD and 480-Watt Power Supply

    Other drives:

    Sony DRU710A / 16x4x16x DVD+RW / 8x4x16x DVD-RW / 2.4x DVD+R DL / 48x24x40x CD-RW / Dual / Nero Software / DVD Burner

    YE Data USB 2.0 All-In-One Internal Floppy Drive

    I am guessing that the ASUS manual is going to explain how to set up the board to set up the RAID...
  3. HoopaJoop

    HoopaJoop TS Rookie Posts: 90

    It looks like that board has a Promise controller on it. They are a staple of the IDE raid market. It shouldn't be too difficult to find information about it.

    For me the important thing to consider when getting a raid controller is performance. The cheaper ones are typically software driven. The difference between software raid and hardware is phenominal. Hardware raid controllers, while expensive, have huge perfomance boosts in that they have their own ram and bios. Of course, bus speeds may become the bottleneck.

    Another important factor is the drive types. Some software controllers, albeit rare, will let you make a raid from most any drive device. This is dangerous because you will not have a very stable configuration if you use, for instance, an EIDE drive with a SATA drive. Likewise, if the drives have different drive speeds your config will s'plode during a read/write operation. Mixing 5400rpm, 7200rpm, and 10000rpm drives in your raid is not a healthy idea. Some controllers may have compensations for this, but I wouldn't trust them.

    Drive size is not that important. Sure if you want to be efficient you should use the same sized drives, but most controllers will normally operate as if all the drives are the size of the smallest drive in your array.

    Sorry if this information is redundant.....guh...stupid pun. I was lazy and didn't read the entire thread.
  4. Phantasm66

    Phantasm66 TS Rookie Posts: 5,734   +8

    Promise RAID stuff is great.
  5. champmanfan

    champmanfan TS Member Posts: 59

    PATA to SATA

    I'm not too sure on RAID and has PATA & SATA got anything to do with making drives into RAID, help! My drives are setup as PATA in BIOS and are speedy @ 7,200 IDE, UDMA Ultra 5 mode (whatever that means).

    I'm guessing the 'S' is Serial and 'P' is Parallel. Is PATA for 40pin cables & SATA for the smaller/narrower 80pin cable. Is that right?

    So if I changed it to SATA would I then have RAID & how much faster is it than my current speeds? My Half-Life 2 loading level screens takes 90+ seconds to load with a AMD Athlon 3400+ 512L2 cache.

    I'd appreciate any help :giddy:
  6. alphnumeric

    alphnumeric TS Rookie Posts: 173

    NO. The controller determines used determines whether RAID is supported or not. There is STA Raid and PATA Raid.

    NO, 40 wire 40 pin and 80 wire 40 pin cables are both parallel IDE cables. The 80 wire 40 pin cable is required for (I believe) ATA 66 and above speeds.

    First off, to use RAID you have to have a controller that supports it. SATA drives are faster than IDE. SATA drives are ATA 150, IDE drives are ATA 133 and below. I believe Ultra DMA 5 mode is ATA 100. Raid can be faster or slower depending on what mode you use, striping or mirroring. For two drives RAID 0 (striping) gives you an increase in read speed. Technically it's not really Raid because you don't have any redundant drives, lose one lose them all. :)
  7. v_empirez

    v_empirez TS Rookie

    I have a raid array 0

    I will put it to compete against any single drive reading and writing and it will out do anything as long as its not SCSI. It read slower cuz they didnt have the ram or cpu appropiate for it. remember the machine is as fast as its slowest piece
  8. champmanfan

    champmanfan TS Member Posts: 59

    Thanks for the advice Alphunumeric. When I bought my PC it says that Ultra DMA mode 5 is 133Mbps for IDE. So it must be right but unless someone has a list for the 'DMA modes' then it's anyone's guess!

    The motherboard I have that I want to put two SATA drives on with my two IDE drives is a MS 6741. I've tried finding out about which SATA drives to use and if I can use them with two IDE drives, so if some buffs could give me a hand - don't clap ;)

    I'm using Windows XP Pro SP2.
  9. ßeetlejuice

    ßeetlejuice TS Rookie Posts: 30

    Compaq Proline 1500 server; P1 166Mhz + P1 166Mhz co.

    I've got a Compaq Proline 1500 server with a capacity of 5 disks of which 4 are taken by 1 9Gb and 3 18.9Gb disks.
    It used to run under Win2k server for the last time, which was installed on the 9Gb.
    I managed to save it from going to the junkyard when the company I worked for closed down. ;)
    I'm planning to make this baby running on linux to start learning and working with server technology.
    Any info I can get somewhere in how to install from scratch and how to configuring it's raid? :confused:

  10. alphnumeric

    alphnumeric TS Rookie Posts: 173

    My mistake, mode 5 is ata-100 and mode 6 is ata-133,
    Ultra DMA
    Mode, Maximum Transfer Rate (MB/s)
    Mode 0, 16.7
    Mode 1, 25.0
    Mode 2, 33.3
    Mode 3, 44.4
    Mode 4, 66.7
    Mode 5,100.0
    Mode 6,133.0

    You should be able to set up a Sata raid array and a separate IDE drive Raid array. I don't believe you can mix and match sata and IDE in the same raid array, if that is what you are wondering. :)
  11. james_k1988

    james_k1988 TS Rookie Posts: 163


    dont i feel like a ******* here lol what is RAID? is it jsut basically linking 2 hd's together into one?

    ...well if i dont ask i'll never learn lol :blush:
  12. champmanfan

    champmanfan TS Member Posts: 59

    Thanks for the drive speeds, although I have never heard of mode 6, has this been around a while? I don't think many people are able to use this because even Western Digital don't have IDE ATA 133 to make use of 133MBps speeds.

    When I posted my question on SATA drives, I meant I would want to setup two SATA RAID-0 seprately from my two IDE drives. Also, would two Seagate Barracuda's 7200.8 running in RAID-0 on a SATA give my system a big speed boost and what speeds could this achieve?

    My case only holds two drives and was wondering what PC cases would hold just 4 drives. It would have to be black and the same height as my current case, 41cm. I don't mind at all if it's wider. I would appreciate advice, please.

    I'll keep my two IDE 200Gb drives on my system for stuff like game patches, storage space for my digital video editing (learning the trade at the moment!) game movies, important file backups and a few thousand of my family's digital photos.

    So if anyone has one of those new Seagate Barracuda's 7200.8 - please post your opinions here, thanks!
  13. champmanfan

    champmanfan TS Member Posts: 59

    You've got to link two SATA drives (not the typical IDE) together that almost doubles your hard disk speed. RAID-0 is better. Once you've linked them, I think the two drives would be seen as one but with both drives capacities added together to give you a huge amount of space.

    Also SATA uses very thin cables compared to the wide IDE cables. Some IDE cables restrict the air flow inside the PC whereas the SATA cables don't, plus they look great.

    Hope that was easy to understand, if not, just ask away and someone will reply soon.
  14. alphnumeric

    alphnumeric TS Rookie Posts: 173

    Maxtor has ATA-133 drives, they may be the only one. I don't see anybody following Maxtor with it now that Sata is here. My RAID PCI card is ata-133 and my new Gigabyte motherboard supports it.

    Western Digital has some 10,000 RPM Sata Raptors. :cool:
  15. alphnumeric

    alphnumeric TS Rookie Posts: 173

    Real-world IDE RAID explored
    What is raid
  16. james_k1988

    james_k1988 TS Rookie Posts: 163

    thanx guys i get it now :angel: never knew there was sumfin like that avalible as well lol i think i need to jump out the ages of windows 98 :p
  17. escarvajal

    escarvajal TS Rookie Posts: 23

    RAID Setup

    I have a Dell Dimension 8400

    with 1 80GB SATA150 HD

    if I am going to a RAID 0 setup

    1. Do I need a 2nd HD of the exact same size and type?
    2. Do I need purchase a RAID controller card or is that function already on the Dell mobo?
  18. KillerTron

    KillerTron TS Rookie

    Seagates are very reliable, and when not quickly replaced.

    Dear Poster

    I have multiple Seagate Barracuda drives, they are not as fast as the Hitachi/IBM Deskstars abut they are much much more reliable. Yes you will get a speed improvement using RAID 0, or RAID 0 + 1, you will get security with RAID 1, and (JOB which some call RAID 2, stands for 'Just One Big Disk'.

    You can happily use any seagate (pair) in combination, try to get a pair with the additional CACHE (8MB for most drives above 80GB) and if you haven't used cached drives then you will need to tell WINDOWS to clear its cache before shutdown. This will prevent any lost data and the dreaded chkdsk routines from running at reboot, Try to partition the drives <= 100gb if you are using win9x or XP / 2000, before the latest service packs, else (even with the latest keep the partitions to <=132GB.)

    One word of advice here, to help Windows and many other Windows and DOS, and Linux/ UNIX, tools 'see' the 'end' of the drive, try to always leave one data sector EMPTY at the END of the physical drive (not at every parition as some suggest).

    You will be very unlikely to have any of the many WIndows BSOD if you do this, I don't know why, but Windows (since B&W, Win286... to WinXP 64bit) all seem to have this problem as do some versions of Linux/UNIX. So leave the last bit, it's usually only about 7.8mb anyway and for a stable system it's far better to do this, than waste hundreds of hours trying to recover drives that have suddenly 'grown' strange problems.

    I have the following SEAGATE Drives (in multiple computer systems, from old 486s through to 3Ghz+)

    2 x 17.2GB Seagate Barracuda's (can't remember exact model numbers)
    These drives are approximately nine years old and still running perfectly.

    4 x 28.8GB (Seagate always uses a bit in the formatting of the drive)
    These are above 6 years old)

    4 x 40GB ST400??
    These drives are 4 years old

    8 x 80GB 4 x SATA 4 x PATA (ST380021a {pata} ST380021S {SATA}
    (many mirrored in raid setups on GA-7DXR / Ga-7VT880 - RZ)
    (Asus A7880, Gigabyte K7 Triton mobo too .. note mobo US, 4 of 6 gigabyte mobos dead so note this! Asus mobos 100% running record since installing.)

    4 x 120GB 2 x SATA 2x PATA
    (as 80's above)

    2 x 200GB barracudas (arriving on Monday.)

    In Twenty years of using PCs I have only had two Seagate drives fail on me, both died within the gaurantee / warranty period and were immediatedly replaced, I live in the UK, the drive had to be posted to Holland and despite this and no Airmail the replacements both arrived in 7 days (less for one just 5 days). One drive that had died was a 10GB, it was replaced with one of the 17.GBs above, which was why I purchased another (to mirror for data backup). This is the best hard-drive customer service record I have come across, many other companies just give you the run around.

    I have used literally hundreds of multiple other manufacturers drives for other people MAXTORs aren't bad, but I've had quite a few die on friends machines, (fitting them to their PCs at their specific requests, despite my advice against it) and many of the different manufacturers drives have failed, and in the most part all have later been replaced with seagates. I.e. Micropolis (SCSI BRICK 30GB) Connor [very bad], Maxtor, and many others.

    The only others I have found seriuosly reliable are both the Hitachis, & IBMs (Hitachi also produce the IBMs) if you check their product names (e.g Deskstar etc.) they are nearly all the same.

    I hope that this information is useful to you, if you have to return a drive try running all Seagates diagnostic software on it first (Seatools), and when preparing the drive (usually preformatted) for use on different or other systems, use only their tools (Disc Wizard) both are freely available from their web site. [see below]

    Send them the generated reports, usually they can phone you with a software 'fix' or with details of how to get an RMA if required. i.e (Spinrite) or for (bootmaster).

    They also have a free HELP file (with font to display it properly) with all the jumper settings for ALL their drives and everything they have made to date, download the latest Seagate version of (disk referencer). goto Support downloads FREE software.

    I hope that you find this information useful.


  19. mikescorpio81

    mikescorpio81 TS Rookie Posts: 293

    Ok, I can understand why businesses & organisations would use a RAID setup, but seriously, is it really neccessary for people at home to use it? I mean, with external HDD's & DVD-RW's etc on the market you can back-up everything you have without having a mirror-image of your HD. How often do u think people at home would need to rip out their HD & quickly replace it with a mirrored copy while their pc is still running?! Seems like a waste of time & $$$ to me but hey ... what do I know?! :giddy:

    Or is RAID used for a more conventional purpose at home? Could anyone please shed a little light on this theory? No disrespect to anyone at home using a RAID setup!! Always eager to learn here guys :grinthumb
  20. champmanfan

    champmanfan TS Member Posts: 59

    RAID Is G8

    I've had my two new 300GB Maxtor DiamondMax10 SATA NCQ 7,200rpm 16MB Cache hard drives for just a month and it's great. Even though they have replaced my two 200GB Western Digital Caviar ATA drives, I've put them into my work PC to replace two 40GB drives that were really really slow.

    I've put my new SATA drives in RAID 0 array because I demand speed with playing FPS like Half-Life 2 that use to take up to a minute to load (now takes just 15 seconds) and various other games, plus I require RAID 0 for digital video editing and audio creation.

    My RAID array is split up into these partitions: (1) 51Gb for main system files & OS even though it takes up just 11Gb. Should have made it just 30Gb (2) 280Gb for programs, games and application. Takes up just 37Gb (3) 270Gb for all my storage stuff like patches, mods, speedruns, digital photos. Mostly just slack for Premiere Pro movie editing. This takes up about 77Gb. I know this brings the total to 601Gb - which doesn't add up - but most drives have more or less than stated.

    It's worked like a dream and I would recommend people to set up most SATA drives in RAID 0 and make the most of the speeds on offer - I got 141MBps from HD Tach. It's only the 10k Western Digital Raptors that can beat my two drives. This is probably because of NCQ (native Command Queing.

    when I bought my drives it quoted speeds of up to 150MBps which is 1.5GBps - so why aren't I getting 150Mb and why have they quoted 1.5GBps as well? I understand the 150Mbps speeds but how do they calculate 1.5Gbps speeds. It's like the SATA2 is 300Mbps = 3Gbps. I think i'm missing the point competely with these speeds.

    The joy will be short lived when the mighty SATA2 standard comes in later this year with 300Mbps speeds.
  21. braket

    braket TS Rookie

    Hi. I have Asus P4V8X-X mobo and 2 80GB Seagate Barracuda SATA setup in RAID1 (done as written in the mobo manual). I installed Windows 2000 and the VIA RAID Utility (came with the mobo driver CD) on the primary drive. Does this mean that my mirror drive is always have the same content as the master drive or do I still have to sync the drives every now and then?

    Please help. Thanks! :)
  22. champmanfan

    champmanfan TS Member Posts: 59

    A RAID 1 setup as oppose to a RAID 0 is one that just copies data from one drive to the other like a backup, only that it's much faster and works on the fly. Unless one of your drives fails, you'll always have the same content on both drives. This is how low-cost servers work do you get less down-time.

    By the way, why do you need to have a RAID 1 setup? Do you run mission critical event programs, etc? If you play the latest games like me just have it a RAID 0 array with faster speeds and double capacity of your RAID 1 setup (160Gb). This is called striping - where data is split across the two drives unlike RAID 1 that copies itself to both.

    I'm sure other members on this board will have more answers to give you and I'm sure you'll be wanting some points cleared up. Gald to assist.
  23. braket

    braket TS Rookie

    Hi. Thanks for the reply. I need to backup data from one drive to the other.
  24. champmanfan

    champmanfan TS Member Posts: 59

    There Are Better Backup Methods.

    Try using a USB2/FireWire 400/800 external drive. Capacities are pretty huge now (2TB+) and are constantly getting cheaper. Use the backup software that comes with your drive to back the whole drive up or use an imaging program like Drive Image that'll copy your drive EXACTLY as it is - bit for bit.

    If you continue using RAID-1 to mirror, then if you get infected by a virus for example, there's nothing stopping it gobbling up all your data.

    If you do use an external drive, schedule regular backup perdiods every month. So your drive will contain multiple backups like January Backups, February Backups, March Backups... So if one backup is either incorrect or didn't backup correctly - you'll have more to choose from. I would recommend no more than 5 backups to keep at a time. Once you reach the 5th one, just delete the oldest and start a more updated one.

    If your drive is just 80GB, then get a external drive of 500Gb. I know it adds up to 400Gb but once you have formatted it, you might end up with just 350Gb.

    Hope this helps :)
  25. kapeed1986

    kapeed1986 TS Rookie Posts: 19

    Redundant Array of Independent / Inexpensive Disks ..
    Inexpensive ... maybe not

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