View Full Version : RAID on Xserve

07-18-2002, 10:30 PM
Been playin with Xserve for a few hours now. Set up HD 1 to boot from, HD 2 and HD 3 are mirrored, and HD 4 is spare/empty. Thought I would do some worst case testing since everthing is clean, and no real data.

1) unmount spare drive per instructions (drag icon to trash), and yank the drive. Reinsert drive. Drive mounts on desktop in about 5 seconds. Feels just like Firewire.

2) DO NOT unmount mirrored drives (to simulate falure). Yank one drive. Second drive is humming along OK; no errors, app on mirror is still running. Reinsert drive. Error message appears that says the disc is unrecognizable - "intialize", "eject", or "cancel" are the options. Select Cancel. Open Disc Utiliy, select mirror, and error says drive has failed and needs to be rebuilt. Push rebuild, and an error states rebuild failed because disc failed to unmount. Quit running app, and then rebuild. Approx. 30 min. rebuild time.

3) Tried several variations of this test, including no ruunning app, and just empty/formatted drives, and the result is always the same: mirror must always be rebuilt, and so both drives are unmounted by disc utility.

So, even though the drives are "hotswap", apparently you cannot swap or rebuild the mirror without stopping all processes on the mirror, so your server is offline.

Better than no mirror for sure, but not that impressive. http://macgurus.com/infopop/emoticons/icon_frown.gif

I guess SoftRAID has spoiled me. http://macgurus.com/infopop/emoticons/icon_biggrin.gif


[This message has been edited by newbie (edited 18 July 2002).]

07-19-2002, 01:02 AM
Hey new,

?Neat stuff none-the-less.

?One thing that comes to mind is all the times I have heard/read that power cable pulls or even worse, data cable pulls are considered catastrophic with IDE drives. That is not considered recoverable like it is for a SCSI drive. I'm not exactly sure why a SCSI drive can handle that while IDE can't and I'll have to go back to my books and find the relevant parts but I am pretty sure that that was the case.

?In fact the very testing being done (where ever it was that this was written up--- grrr) was for IDE mirror failures and that you couldn't replicate the failure properly by just disconnecting the drive. I also am surprised that the server didn't crash since in most instances that write-up said you would see an instantaneous system lockup, maybe they designed the XServe a little better than you think? Of course the treatise I was reading was solely written pre-OSX so there may be a few differences there.

?I'll look around and see if I can find it. This is my very busiest time of the year and I have very little time or energy left until after next thursday, end of fiscal year, taxes, inventory and all. So it may take me a bit, I'll see if I can find some sort of testing parameters for you.

?Thanks for the updates,


07-19-2002, 01:30 AM
Hey Ricks-

Wow, good to know. I kinda wondered about that (pulling the drive compared to an actual failure). Based on your info, maybe I should be more impressed. Not that I am disgusted or anything, I was jsut hopeful that I would not have to take down the server to rebuild.

But the improtant thing is that it just kept humming along, through several tests...and apparently what I did was "worst case" then.

I have not been through all the documentation yet, but I gotta believe that if the box could not handle pulling a drive without unmounting first, there would be some mighty big warnings all over the place. apple is pretty good about that sort of thing; stuff for first-timers. Have not seen any in-depth info on troubleshooting/FAQs about RAID, or warnings/recommentdations about pulling drives.

Thanks for the offer though, it would be neat to know the why/how, but don't kill yourself...it is what it is, and barring a serious red light we are gonna use it as is.

If the ATA RAID setup chokes as was mentioned by several folks in the other forum, then it looks like our only choice is an external SCSI RAID box. I can't see any easy way to shoe-horn SCSI drives and cabling into this pizza box without serious modifications.

Since I can't boot to OS 9.x, what is available to test drive performance? Seems like I saw somone here mention an Apple app - Basher or Trasher (or somthing evil sounding like that) for OS X?

07-19-2002, 02:17 AM

?Actually a full set of speed testing tools that you should try out. I put a copy on the Gurus ftp site in the Benchtest apps folder. You can also get them from Apple here:


07-19-2002, 04:37 PM

Can you point me to the Gurus ftp? Never been yet, did not see a link anywhere, and the search feature is down.

07-19-2002, 04:43 PM

07-20-2002, 10:22 PM
I actually tried that before I posted, but no luck...then I added the "/". Bingo.


07-23-2002, 11:55 AM

OK, finally got it. Do you have recommendations/standards for configuration of DiscBasher? I will post results if anyone is interested; mirror only though. Got to have this baby online to about 95 users soon, so I won't have time to test RAID 0.