RAID 5 back to RAID 1 -- ICH10R

Toggle sidebar Toggle sidebar
D

dprice74

Distinguished
Jan 3, 2010
10
0
18,520
My RAID 5 array of 4 1TB drives is unbelievably awful, < 3MB/s writes -- yes, you read that correctly. I can live with it now because reads are decent and my boot drive is a 256G SSD so the RAID array is now strictly long-term storage, but still, AWFUL. Never should have migrated from RAID10 to RAID5, Intel sucks at parity. Big middle finger extended to you, Intel.

So, there's no good, reliable way to fix Intel's horrible RAID 5, I've checked. There ARE a bunch of crappy fixes that don't help, please don't list them here. I'm moving on.

Anyways.... since there's no migration path from 5 to 1, my plan is a brute force copy to an external USB2.0 HD, wipe the RAID5, rebuild a RAID1, copy it back. It's about 2T of data. Again, I have the SSD as my boot and it's long-term stuff so I don't really care too much about how long it takes.

So, my question, which is sort of dumb, but... is the process of making a new RAID1 any more complicated than just going through the Intel menus, i.e. drop the RAID5 volumes and build a RAID1? I'm sure I'm not the only person to have ever done this.

Thanks.
 
Solution
P
Sort by date Sort by votes
P

Pinhedd

Champion
Aug 7, 2007
10,342
20
56,965


Intel's RAID5 should be faster than that. Calculating parity blocks is not that complicated. Something else may be wrong, certainly if the drives are getting old.

That said, it is no more complicated than you suggest.
 
Upvote 0 Downvote
Solution
D

dprice74

Distinguished
Jan 3, 2010
10
0
18,520
[not sure what happened with this post]

Thanks!

It used to be faster, when I first switched. "Hurr durr," thought I, "I'll get an extra TB of space!" It gradually got worse and worse, though.

Best as I can tell, there's some problem with how Intel writes parity blocks, such that it can end up spinning a LOT, particularly with even numbers of drives, and the problem gets progressively worse over time. I assume simple mirroring won't have this issue.

As popatim pointed out, a waste, but seems like the best option available if I want backup, and I don't need the space that badly. With this + the SSD, I can avoid buying a new PC for a couple more years.

This was originally a RAID10 build, but I don't need the performance of striping anymore.

I guess if it's a drive issue, I'll find out soon :)
 
Upvote 0 Downvote
Hawkeye22

Hawkeye22

Glorious
Feb 10, 2006
11,442
1
49,065


If you think RAID is a backup, then you're in for a big surprise. A virus or accidental file deletion will cripple RAID just as it will cripple a single drive. RAID is for redundancy - if one drive fails the system will continue to run. It is not a backup.

 
Upvote 0 Downvote
D

dprice74

Distinguished
Jan 3, 2010
10
0
18,520


Argh, you caught me before I edited that out! Yes, RAID is NOT a backup, I knew someone would nail me on the sloppy terminology :)

 
Upvote 0 Downvote
D

dprice74

Distinguished
Jan 3, 2010
10
0
18,520
Well, THAT was mildly irritating. :)

So I back up the data, everything looks fine, I wipe the arrays, make new ones, restart and... SSD is no longer bootable. :ouch: NO BOOTABLE DEVICE etc.

My guess at what happened is that the RAID drivers were on the arrays that got wiped. :pt1cable:

So, not a huge deal, I booted off my USB Windows install/repair thumb flash drive and... it says there are no Windows installations to repair. :??: Ruh-roh. Based on a related thread here I tried unplugging and replugging the SSD, which did nothing of course. I used the repair console to install the RAID drivers after downloading them on a another computer, which seemed to work okay for the new HDD partitions but hung when I tried to put them on the SSD. Still no love on reboot.

Well, think I, I was going to install Windows on a partition anyway... So I did that. And it booted fine. And I can see everything on the SSD.

Panic receding, I did some more flailing around in BIOS. I'm honestly not 100% sure how I fixed this. One of the last things I tried was flipping back and forth from RAID to AHCI, which made Windows very upset, but also finally got Windows Repair to notice -- hey, there's a Windows install on this SSD! Let's repair it! :bounce:

A couple reboots later, everything is fine again. Well, several reboots, because did I mention it's also in the middle of a giant Windows update? So yeah, good timing. :sarcastic:

Now, I just have to copy back my data, which should be relatively simple. Copying it to the external 3TB USB hard drive ran into some odd issues with how Windows treats stuff in the "USERS" directory, so if anyone ever decides to copy across an abandoned Windows installation just for the data, be warned: you DO want to check that it copied everything (because it probably didn't). I found TreeSize to be very helpful for this.

BTW, write speeds now normal again with simple mirroring :) So, apparently no issues with the disks themselves. Going to pin the blame for those sloooooow writes on parity.
 
Upvote 0 Downvote
popatim

popatim

Titan
Moderator
Dec 2, 2009
38,904
980
135,890
Ya know I had kind of a funny issue like you too the other day. Customer runs raid10's and wanted to upgrade his drives.. No problem but when I went to reload windows I get the Windows cant detect a drive... not a problem. I click the option to load drivers and it brings me to the file browser... which clearly lists the raid10.
 
Upvote 0 Downvote
D

dprice74

Distinguished
Jan 3, 2010
10
0
18,520
Thanks, that's interesting.

I guess Intel's RAID driver location must be stored somewhere in the bootup sequence, and it expects to find them there, else no boot. Maybe the repair/install program can go look for them, since it doesn't run from the RAID drives...
 
Upvote 0 Downvote
P

Pinhedd

Champion
Aug 7, 2007
10,342
20
56,965


Something like that.

There's an Intel RST/RSTe BIOS OPROM and/or UEFI Driver located in the firmware. If the storage controller is in RAID mode, one of these is executed during the system startup but before firmware passes control the appropriate boot loader. The OPROM/Driver is a software module that allows for a RAID volume to be readable. It is not a Windows driver.

One of the first things that Windows does when it boots is unload and undo a number of tasks performed by the BIOS/UEFI firmware, including unloading some of the firmware's drivers and loading its own. Some operating systems such as MS-DOS rely heavily on firmware services (this is why MS-DOS will work just fine on a modern PC with SATA and USB) but Windows does not.

It will unload the firmware's RAID module, and replace it with one that cannot interface with the RAID. The RAID interface must be either supported natively (not always the case), or be supported by Windows drivers provided by Intel.
 
Upvote 0 Downvote
D

dprice74

Distinguished
Jan 3, 2010
10
0
18,520



Ahhhh, that explains a lot, such as why Dell/Alienware would/could place a driver on the thing it drives :)
 
Upvote 0 Downvote
You must log in or register to reply here.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom