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Mirroring Controllers - What have been Your Experiences?
Today's installment is a lengthy (but hopefully informative) piece on mirroring controllers. Ever had weird problems with a FastTrack TX2000? Are you curious how well HighPoints RocketRAID boards are really supported? Ever wondered which controller gives you the best performance for every dollar spent? In true Slashdot tradition, we're taking the issue and throwing it out to you, the readers. Futurepower(R) is willing to start us off with a wealth of information on his experiences, and I'm hoping a few of you are willing to do the same.
Futurepower(R) asks: "What experiences, both good and bad, have you had with mirroring controllers? Are there manufacturers I haven't found?
For those who are interested but don't have experience, mirroring controllers (RAID 1) provide several advantages:
ECS (EliteGroup) has made 11 motherboards with on-board RAID mirroring controllers. One of them, the P4VXAD, has a Promise controller and costs about $52. What's that about? Employees at Fry's tell me that ECS has the poorest quality control of any of the motherboard manufacturers that they sell. To me, ECS motherboards seem to have surprisingly high quality. However, we have only tested three, and only one extensively.
Silicon Image makes, or made, their 0680 RAID chipset, and Koutech Systems sells the IOFLEX-Pir133 using that chipset. It costs $25 retail. I tried a Koutech card and had a lot of trouble with it, even after updating the BIOS. I talked to an application engineer at Silicon Image and a manager there. I was told that SI bought the technology from another company, and apparently it is no longer supported, doesn't work well, and the company does not intend to put more money into it. I found that the Koutech card corrupts files. The card gives a Stop 07B error when going into the Windows XP Recovery Console, unless the driver is loaded by hand, every time. I lost a lot of time with a product that apparently should not be sold.
My experience with mirroring controllers is mostly with those from Promise Technology. I've been using Promise mirroring controllers since they began making them.
The good about Promise:
The Acard controller supports SuSE, Red Hat, Caldera, and Turbo Linux, it says. But remember, Froogle found only one vendor.
HighPoint says they support Linux: "Linux Red Hat 7.3 & 8.0 (Software RAID Only)". This apparently means the card does not support Linux at all, since Linux has software RAID built in.
So, that's the extent of my knowledge and experience. Can you provide further insight?"
For those who are interested but don't have experience, mirroring controllers (RAID 1) provide several advantages:
- They prevent data loss when a hard drive fails. The other drive in the mirror takes over seamlessly.
- Reading of data is considerably faster since the controller reads the data from the drive that has a head closest to the data.
- You always have a full hard disk backup that you can pull from your system at any time, such as before installing new software.
- You can clone a Windows XP drive using the RAID card, and you will have a bootable copy. This is valuable, since the Windows XP file system cannot copy all of its own files. (Don't flame this; it has been verified many times by Microsoft employees, who often suggest using the third-party tools.)
- Promise Technology's FastTrak TX2000 is available for about $85 delivered.
- HighPoint's RocketRAID 133 costs about $80.
- ACARD Technology's AEC-6880 costs about about $85. Froogle found only one vendor. That's scary.
- Adaptec makes the ATA RAID 1200A, which is available for about $59 before delivery charges.
ECS (EliteGroup) has made 11 motherboards with on-board RAID mirroring controllers. One of them, the P4VXAD, has a Promise controller and costs about $52. What's that about? Employees at Fry's tell me that ECS has the poorest quality control of any of the motherboard manufacturers that they sell. To me, ECS motherboards seem to have surprisingly high quality. However, we have only tested three, and only one extensively.
Silicon Image makes, or made, their 0680 RAID chipset, and Koutech Systems sells the IOFLEX-Pir133 using that chipset. It costs $25 retail. I tried a Koutech card and had a lot of trouble with it, even after updating the BIOS. I talked to an application engineer at Silicon Image and a manager there. I was told that SI bought the technology from another company, and apparently it is no longer supported, doesn't work well, and the company does not intend to put more money into it. I found that the Koutech card corrupts files. The card gives a Stop 07B error when going into the Windows XP Recovery Console, unless the driver is loaded by hand, every time. I lost a lot of time with a product that apparently should not be sold.
My experience with mirroring controllers is mostly with those from Promise Technology. I've been using Promise mirroring controllers since they began making them.
The good about Promise:
- Promise has been selling RAID 1 controllers a long time. They work.
- Promise controllers can clone a hard drive quickly.
- Now some motherboards have Promise mirroring chipsets. You can get the entire motherboard with the Promise controller on the board, for maybe $50 more than the Promise controller card alone.
- Linux drivers are available. The web site says, "Windows XP/2000/NT4/Me/9x; Novell NetWare 4.1x/5.x; RedHat Linux 7.0/7.1/7.2; TurboLinux Server 6.5; TurboLinux Workstation 7; SuSE Linux 7.2; OpenLinux 3.1" Does that mean that later versions of Linux can't use this card, or did Promise forget to update the brochure PDF file?
- Promise controllers work fine under DOS, but there is no error reporting if for some reason the mirror breaks.
- Promise mirroring controllers have a software feature called "sychronization". I've asked many times over the years why it is necessary, since mirrored hard drives should be synchronized 100% of the time. I've never gotten an answer. Recently I've been told by Promise technical support people not to use synchronization, since it has caused problems. It sounds like some technical problem is being hidden.
- Promise does not support their oldest mirroring controllers under Windows XP. This is a problem since there are many business computers that are used for data entry. A Pentium II is as fast as is necessary. Windows 98 is stable with only one program running. Now those computers need to be converted to Windows XP, since Microsoft has declared that its operating systems have a curious quality: They die. (According to Microsoft, it doesn't matter that at least 100,000,000 people are using Windows 98 worldwide, it came to the end of its life on "30-Jun-2003".)
So, it is necessary to buy another controller for old data entry systems. Notice that Microsoft and Promise could decide to play this game again, and I would like to avoid the second round of buying and installing even another controller. I'd like to find a company that continues to support its products.
The speed of computers used for data entry does not matter, but the security of the data does. Hard drive failures are becoming rare, but a hard drive failure can cause a lot of problems on a data entry computer, so mirroring is required. - Some Promise controllers, especially those on motherboards, take a long time to boot. Dots crawl across the screen even if no drives are connected to the controller. Is keeping the Promise name on the screen a time-wasting sales message from Promise? Recently Promise released a BIOS upgrade for some of its cards that reduced the dot-crawling time. However, there is apparently no upgrade for Promise controllers on motherboards.
- About 2 months after I reported problems, Executive Software said they found a bug in their Diskeeper defragmentation software that might cause data corruption when used with Promise controllers. They said everyone using Diskeeper should upgrade to the new, free, minor version. I've seen no problems since then.
- Promise Technology's sales literature can be disgusting. This is the second sentence in Promise's description of the FastTrak TX2000: "The FastTrak TX2000 ATA RAID card supports Ultra ATA/133 drives to rock workstations and boost small (or large) office servers like never before." To me, this is obviously written by someone who knows nothing about the product and doesn't care.
- I find the abundant use of PDF files and unnecessary JavaScript on Promise Technology's web site annoying.
The Acard controller supports SuSE, Red Hat, Caldera, and Turbo Linux, it says. But remember, Froogle found only one vendor.
HighPoint says they support Linux: "Linux Red Hat 7.3 & 8.0 (Software RAID Only)". This apparently means the card does not support Linux at all, since Linux has software RAID built in.
So, that's the extent of my knowledge and experience. Can you provide further insight?"
I just want to say that it's absolutely impossible to read that much italic. My eyes are bleeding.
look
That's all I'm sayin...
Can you spell 3ware?
They do more than just mirroring, and aren't cheap, but if you wants the quality, you gots ta pay the piper.
Drivers are in the Linux kernel, and have been for some time. ATA or S-ATA versions available.
My thoughts on the Promise FasTrack controllers:
We use 'em at work. On the Windows 2000 side, they come with decent management software and for the most part, are relatively reliable.
However, they are far from perfect. I've had several W2K servers blue screen when doing a hot-swap. Joy.
The FreeBSD drivers are bloody stable as hell. No complaints.
The Linux drivers provided by Promise are, IMHO, a POS. Pain to compile. No management software. Diagnositics are limited. As a result, I'd go with a different IDE controller card if you want it for Linux. YMMV.
I have used several Promise FastTrak RAID controllers and have had varied results, but all in the "crappy" range. Their drivers are proprietary, so you have to stick with the pre-compiled kernel module. This means you also have to stick with a pre-compiled distro kernel so the symbols match. Promise has always been several kernel versions behind, so if there is a kernel security upgrade, you have two choices: 1. patch the kernel and break the Promise card or 2. Leave a vulnerable computer up and running. You can generally force a promise module into a non-matching kernel, but I've always been hesitant to do that.
I have switched every Promise installation to 3ware cards because of this. They are open source drivers, very current, and perform well. Their tools run as a web daemon under Linux so you can check status/reconfig on the fly. Really amazing Linux support, and a reasonable price... (and no, I'm not affiliated...:) )
"Just another damned fool idealistic crusader..."
The purpose of a raid card is improved reliability. Thus, you shouldn't try to cut corners on quality control to save a few bucks. After all, you're already springing for two drives.
I have had very pleasant experiences with 3ware controllers, both under linux and Win32. Currently I have a 6400 running under Suse 7.3, and three 7400s running under RedHat 8. With some hotswap drive bays, you can even unplug a drive with the system running.
They might cost a little more, but they're widely used under more grueling conditions than the more dirt cheap designs. Also, if you're simply doing raid 1, you can use one of their previous generation cards with no performance penalty, and save a bunch of bucks.
I haven't played with RAID's other than RAID5 much, but here's my experiences. Maybe they'll help your opinion.
:)
/proc/mdstat .
I've used several different external RAID5 solutions, including the Promise TX8000 and Radion arrays (and a bunch of no-name brands too). Those all worked beautifully, and survived failures without any significant problems.
I've worked with four internal hardware raid solutions. Two were the Adaptec AA-130 cards years ago, and the most recent two were Promise SuperTrak SX6000. One belonged to a friend, and one went in my machine.
My friend had several problems with his. I'll leave his story at that.
I put together a nice dual processor machine for a large photo archive site. It needed lots of space, which is why we needed the RAID5. It also needed to take up as little space as possible, so we opted for putting 6 drives in a 2u case with the SX6000. The card was incompatable with the newer chipset of the motherboard. It took two weeks of daily calls to tech support before we gave up. A week later, they released a firmware update which addressed this problem. The SX6000 doesn't handle heavy read or read/write traffic very well. When we made it an active web site, the server would crash very frequently with errors about the array. If we kept the traffic slow, it worked fine, but that what we wanted from this machine. This array solution proved to be non-functional for us, so we made the machine a backup machine, so now we have like 600Gb of storage space to back servers up to.
I've heard a lot of good things about 3ware, but haven't tried one myself yet.
I've been experementing with Linux's software RAID's. I've used RAID1 and RAID5, and they both work great. I've had a drive fail on two so far, but for the number of drives we use, that's acceptable. They rebuilt fine sticking in a new drive, with very little performance hit. I do like that Linux gives decent statistics in
You seem to want multiple platforms, so I guess Linux software RAID isn't much of a solution for you.
I can simply warn against the Promise SX6000. It should have been a good card, with Promise's reputation, but I was severly disappointed.
Serious? Seriousness is well above my pay grade.
Everyone knows Linux is quite a bit more stable than Windows. I really don't have any need to do this kind of redundant replication.
/" as root on your Linux box, again,
kiss your data goodbye regardless of
mirroring.
Assuming you didn't mean that as a troll...
HDD mirroring generally provides protection from *hardware* failure, not software glitches. If Windows suddenly decides to overwrite your porn collection, a RAID controller will faithfully do it on both drives. If you accidentally do an "rm -rf
On the other end of the spectrum, however, is OS-level mirroring. I have only experience with Linux RAID-1, both that has never failed me either. I have run software RAID-1 for many years and have only (long ago) had problems where I had to "raidhotadd" a drive from a mirror set that was no longer recognized.
My recommendation, based on both performance and ease of use, is to use a 3ware controller. That coupled with Linux LVM makes disk management and resiliency a breeze.
My only disappointment with the 3ware controller is that one cannot make take a single disk with data on it, add a second disk and tell the controller to mirror the first disk to the second. With the 3ware, you will lose the data on both disks when making a mirror. (So says 3ware tech support.)
the growth in cynicism and rebellion has not been without cause
All of the cards listed are a joke. They are "semi-software" RAID cards. They are crap compared to the real deal, such as cards made by 3ware and the like. Cards with actual processors/cache/etc. on them, and not just some hook into a hard drive interrupt.
If you want to go cheap, you're much better off using Windows 2000/XP's dynamic drives/mirroring ability in software.
I never will understand why motherboard manufacturers use Promise/Highpoint chipsets on their "high-end" or "server" boards. Complete waste of time.
Not All Who Wander Are Lost
Unless I'm mistaken these cards don't do RAID anything. Indeed, they are ordinary controllers that have a few extra functions, all of which are basically hardware acceleration for RAID operations. The critical bits of the RAID are still done in software.
With that said, if you're going to do software RAID, you might as well just do it. I've been using VINUM on FreeBSD for a long time, there are other options for FreeBSD and for Linux. The better ones take full advantage of the "dual read" property of mirrored drives at the kernel level. Best part, no special hardware required. If something breaks buy any old ATA card and you're back in business since it's all in software.
If you need RAID-4 or RAID-5, a dedicated card might be a good idea. For mirroring I think software is superior.