fakeraid for windows, kernel softraid (md) for linux?

[dirk_salewski]

Hello NG,

recent mobos mostly have some sort of bios raid, which can be used with dmraid if you want to dual-boot windows. However,

• as shown on http://blog.shaf.net/?p=6 kernel softraid (md) beats fakeraid (dmraid) on performance
  
• if your mobo dies you need another mobo with same chip (say ICHxR) to get access to your data, whereas md would (in theory) allow to move on to a different mobo without problems
  
• afaik at least ICHxR in RAID mode shows up as normal ahci controller unless using dmraid, without losing functions like ncq and the like

Wouldn't it be possible then to use the bios raid functions for installing a gaming windows raid0 (when it dies, it dies, so what), and access the free rest of the disks just normally, to build a "real" kernel softraid on it?

Can anybody confirm point three, and did anyone try this? If it works I'd probably buy a ICH9R-based board, if not I'd probably go with a (cheaper) non-raid ICH9-model.

Greetings,

DS
_________________
Egal was Du kochst: Karl Marx.

[likewhoa]

[monsm]

Yes, agree, think you are stuck with using dmraid if you want to have both windows and Linux on the same raid set.

You could of course get an additional little windows gaming hd, or better still, stick with Linux games. You'll have to forget about the latest games from the big vendors, but there are still a decent amount of good games for Linux (there are some threads on that here somewhere). A lot will run under wine too, if you know how to configure the ting (bit of a beast if you ask me).

I wouldn't worry about the mobo dyeing. Unless you are overclocking or stab your screwdriver through it, the chances are very small. I have been running the same raid-0 set using dmraid for about 5 years now. No problems, touch wood. I try to take backup on dvd-rw though.

The weak point will be the harddrives themselves, not the mobo. When i set up my machine, I run a full surface scan and tests on the hard drives, to make sure they where ok. I might check one of these days to see if I can find some number on MTBF (mean time between failure) for my drives. Although harddrives tend not to break unless they are already damaged when you install them, or if the machine gets moved around too much, they will break after enough usage. Hopefully I get around to upgrade my old AMD +3200 machine before anything goes seriously wrong.

Here's my set of rules: Get good quality hard drives, test them first, be careful if you have to move your machine, take backup of important things like photos, email, music files, other documents you are writing or working on, save-game files (maybe your /etc tree as well, might save some time if you have to rebuild).

[dirk_salewski]

Thank you for the answers, and that's more or less what I expected. However, I do not *really* want to use win and lin on the same raid set. Those ICH9R-Controllers know a feature called "matrix raid", which allows you to define two different stripesets on a pair of only two disks. I thought that this probably could mean that the bios-fakeraid-controller partitioned the disks, using a partition type of its own, which should then be viewable by cfdisk. If this was the case, I could have defined a bios-based array including only a small PART of each disk (25G each, say). What I would expect to see with linux then would be cfdisk /dev/sda (or sdb) to give:

1: [strange partition type used by controller], 25Gig, primary partition (=>sda1, sdb1)
2: large unallocated space (=>sda2, sdb2)

OR

1: [strange partition type used by controller], 25Gig, primary partition (=>sda1, sdb1)
2: [strange partition type used by controller], 475Gig, primary partition (=>sda2, sdb2, so far not used by controller)

Since I don't care about the data on that windows fake-raid partitions (sda1 and sdb1) I wouldn't bother to try reading it from within linux and instead just use cfdisk to create more partitions in the non-used area, which I could then use with mdadm. I wouldn't even install dmraid then.

[monsm]

[dirk_salewski]