Running a RAID5 array with 2 SSD's and a mechanical hard drive under XP possible ?

[steve2470]

My son is using one of my old computers which has two SSD's. He added an old mechanical hard drive for storage of his videos and MP3's.

I'm being lazy here, but is there any way he can run the SSD's as a RAID5 array and the mechanical hard drive under Windows XP ? He's already tried and XP cannot see the mechanical hard drive. So far I've left him alone to figure this out, but now I'm curious. Thanks a lot for your time.

Steve

[Dawgs]

1. Not sure, but I use an external NAS to handle my RAID5 configuration. n/t

[Renew Deal]

2. I think a lot of machines don't like this

Especially if they weren't designed for raided disks. Depends on the machine and the SW or raid controllers. Sometimes those SSD's are raided without you knowing.

[Dead_Parrot]

3. Depends on the goal...

It'll run like a dog and it's dodgy as hell, but it can be set up - http://www.tomshardware.com/reviews/windowsxp-make-raid-5-happen,925-2.html should do the trick.

So if the goal is to tinker for the sake of it, go ahead.
If the goal is to get a fast and stable machine, run away.

[steve2470]

4. Thank you for the link and your time.

I'm reading the article to see if that RAID5 array AND a mechanical hard drive can be run at the same time, the RAID5 for most tasks and the mechanical hard drive for storage.

[foo_bar]

5. a raid5 needs a minimum of three disks

...and combining the SSDs with a mechanical drive in a single array would turn the SSDs into expensive Seagates for every purpose (i.e., access time, write throughput). If you're talking about a RAID-1 on the SSDs and leaving the mecha unRAIDed, that shouldn't be a problem provided the storage controller supports it (not sure if you can do software RAID without XP Pro or even Server)

[Dead_Parrot]

6. ah...

Sorry, I mis-read the OP. You can't run raid5 on two disks - you need 3+. You could set the ssd's up as a stripe or mirror set (raid 0 or 1) and throw the hdd in for extra storage, but again beyond tinkering fun you probably won't score any performance out of it.

[steve2470]

7. thanks for your help so far, my bad about RAID5, now......

I don't mean to be dense but I've never attempted RAID0 or RAID1 on XP with an additional mechanical hard drive thrown in.

So far his copy of XP SP3 is not showing the extra mechanical hard drive. Could it be the motherboard's fault or what are we doing wrong so far ? Thank you again for your time.

[HopeHoops]

8. The external is probably USB2 and an XP box is likely to only handle USB1.

Also, the characteristics are way out of line for trying to build a RAID5 array. Both SSD drives will be in hyperspace while the mechanical drive is just spinning up. You also do NOT want your system drive in a RAID5 volume, especially one that small. Mirroring is the best bet for system drives. Just use all of the available space and BACK THE DAMN THING UP!!!

DVD-R discs are cheap. Just backup what's important and fuck the rest. If the system disk goes you're looking at a reinstall anyway.

[wandy]

10. Spot on again.

Not only whart you said, but for any type of RAID all drive must have exactley the same charistics. BBCCHH must equate exactly. No mixing and mataching. BBCCHH? Sorry I'm old.

[HopeHoops]

11. That's not technically true. All of the PARTITIONS must be identical.

Well, technically the plex, not the partition, but for the most part you use a partition as a plex. You can spread them out over different drives for efficiency, but usually there's not a good reason to complicate it like that.

[wandy]

19. Yes. Yes. Sorry, showing my age.

Back in the days when harddrives had tails, and weighed 750 pounds. And it wasn't exactly what we think of as RAID today.

[HopeHoops]

20. Yeah, I remember a certain 300mb beer cooler with 12 platters.

[DissedByBush]

9. Sorry, you can't

RAID5 requires at least three drives. They will also have to be the same size (if they're bigger, most controllers will ignore extra space and you waste money), and preferably the same kind and spec, although there's wiggle room.

If you have two equal drives to use you have to ask yourself what you want.

If you want redundancy (if one fails there's no data loss), you want RAID1, which mirrors the disks.

If you want speed you use RAID0, which stripes data across the disks. Warning, now if one of two drives fails you lose everything on both drives.

If he's just running Windows and wants it to run faster, then RAID0 is what you're looking for. IIRC you can't do that to the Windows drive, so you need to use the motherboard's RAID utility if there is one (Windows sees the two as one drive).

If XP can't see a regular mechanical hard drive, then you have other issues besides RAID. If the computer's very old and the drive very big, the BIOS may not be able to see the drive. Or you just have it hooked up wrong.

[HopeHoops]

12. Mirroring is best with two drives. Yeah, half the space, but safe.

Nothing beats a good backup regiment, but if you need 24x7 live access, mirroring and RAID5 are the only ways to go. In critical systems, you have to have a hot-swap drive on a separate controller than the RAID5 drives and each of them should be on their own controller as well. That's getting a bit over the home user budget, but it will keep the array running under damn near any conditions (although I did have to deal with one exception).

[DissedByBush]

13. I only wish I could afford the setup at work

14 hot-plug 10K SCSI drives in a 4U, two hot-plug fiber controllers running 7 drives each. A few of these.

All RAIDs of course allocated across controllers, for both speed and redundancy.

But most of it was RAID10 because the write overhead on a RAID5 is not good for a highly transactional database, performance during a failed drive condition is atrocious, and the loss of two drives before one can be rebuilt guarantees data loss (in a RAID10 the second failure only creates a chance of data loss, not a surety, and a drive in a RAID10 rebuilds faster). Database and log files are balanced across RAIDs on different boxes to spread the risk out even more. RAID5 we use for local backups, which are copied to tape every day and duplicated to off-site.

I hit nirvana when we got some EMCs with SSD storage. You won't believe how fast I/O goes across several striped SSDs. Everything's instant.

Now if only I had an IT budget like this at home...

[HopeHoops]

14. 10K?

Sun had FO interfaces for their arrays in the 90's. They were fucking fast (and not limited by SCSI distances), but SSD is frighteningly fast. My 5.4" mini is SSD and I love it. Cost may be the biggest obstacle now, but that's going to change. Hard drives will be going the way of the 5 1/4" floppy. Hell, thumb drives have seriously dropped in price and I use those for backups all the time. They're sort of the new floppy, but they hold a lot more.

On Edit: Ironically, the more physical drives involved in a RAID5 volume, the less storage space you lose, but performance takes a hit. Rebuilding isn't so bad unless you use the parity drive. Either way, the more physical disks in the volume, the harder the performance hit. I like a five disk array over five controllers with the configuration partition and hot swap on a sixth controller. I've dealt with a lot of drive failures and never lost data. But yes, two down and you're fucked.

One of the biggest mistakes people make is to put multiple physical drives on the same controller and the same volume. If the controller goes, you're SERIOUSLY fucked.

[DissedByBush]

15. 10,000 RPM

SCSI to the controller fiber out to the network.

At my last database job, the database file storage had been configured for RAID5 when I got there. Then a drive died not long after. Database performance immediately dropped through the floor as it had to use the striped parity across five drives to reconstruct the missing data for each read. It dropped even more during the rebuild because the system was constantly reading for the rebuild as it was trying to reconstruct individual requests for data. With customers screaming I had to stop the rebuild and limp along on the reconstructed data until that evening when I could take the database offline and rebuild.

I reconfigured everything as soon as I could, and it was smooth sailing even after a later drive loss (nobody noticed we'd lost one). RAID5 is great for holding a lot of large files to be read, but stay away from it for anything highly transactional.

"My 5.4" mini is SSD and I love it. Cost may be the biggest obstacle now"

I never bothered to ask how much that EMC shelf full of 128 GB SSDs cost. I don't want to know, probably more than my house. But I had to make a case to get any space on that shelf, only the most performance-sensitive applications allowed.

I have yet to go SSD at home, $$$ as you mentioned. I played with an SSD Mac at Best Buy, sweeeet.

[HopeHoops]

16. Ah, got it. As for SSD, the mini came pre-installed with Linux.

The "drive" is more than sufficient for that machine, like 24GB. I paid under $500 for it. It's light weight and the battery lasts almost six hours under heavy load.

It helps to configure the RAID array so each volume has a different purpose. Size has certainly changed!!! The array I had the most experience with was a 30 disk Sun array - it was a big deal when they came out with one that could use 4 GB drives instead of 2GB drives.

I also hooked up a 1/4TB array that was in a case larger than a refrigerator! At the time, that was a shitload of storage. Things change. Just in this room I've got about 15 TB between my development box/server, my laptop, and all the external drives (some on 24x7, others as needed). And I remember the wonder of moving from 13 sector to 16 sector floppies on the Apple II. Damn we use a lot of storage space now!

[DissedByBush]

17. We definitely do store a lot now

We've mostly moved off the local RAIDs and onto EMC now. I have no idea what they're holding, but it's a few 42U racks full of drives 500 GB and up. At home I just have a few externals. I'm sure I'll eventually build a file server.

The massive addition to storage does sound strange, since I remember the tape drive on my Atari, and I was excited to get a 90K disk drive for Christmas.

But then I had one song on the Atari, a very grainy-sounding Van Halen track in mono, that took 30K. I have thousands of songs on my computer now, quality all but indistinguishable from CD, but file sizes in the multi-megabytes. I remember working on video in the mid-late 90s. We had hours of raw video to assemble into a 30-minute presentation at TV resolution. We bought a 30 GB hard drive to do it. How much storage would you need to do that in 1080P these days?

[HopeHoops]

18. A SHITload.

Sorry, it's 11:20 and my head's still fuzzy. It's going to be a LOOOONNNGG day.