Re: [gentoo-user] Creating RAID devices

[Scott Storck]

Emanuele Morozzi schrieb: Me: Hallo, I recently passed to udev, so now I cannot use my Raid. Gentoo si installed in /dev/hda. The Raid is a striping raid composed of /dev/sda /dev/sdb and consists of 4 partitions. I created it installing windows (work reason). The SATA controller is a Silicon 3512. Before, with devfs, I used dmraid to create dev/mapper/sil<something>{1,2,3,4} and mounted direclty using this devices. I had to remove dmraid eBuild from /usr/local/portage (or something like that) because it blocked the "emerge -uD world", and the devices now are disappeared (i.e. using dmraid the devices are not created). I need to create them manually but I have not found the right way to do it. I someone knows how to create this devices, please tell me. ************************************************************************* By the advices of you (Scott Stork), Richard Fish and A. Khattri I checked the kernel .config to see if there was this line CONFIG_BLK_DEV_DM=y. I found this line compiled as module without autoloading at boot. Now, with the kernel 2.6.10-r6 using dmraid I have the devices. With this new one dmraid & dmsetup says there are no devices found. At boot time while autodetecting md array no error is encountered. I use the dmraid tools, but they are not in portage yet. Why not, I don't know. There has been a bug open in bugzilla about this for a long time, but nothing (noticabliy) is happening with this. I however, boot from such a partition, so that ebuild alone doesn't help me. I went the route of using an initrd which runs "dmraid -ay" which creates the device nodes. I would reccommend to you, that you also use an initrd containing dmraid, even if you don't boot from such a partition. This way the devices are available when the normal system starts. I started off using the script and linuxrc found here http://tienstra4.flatnet.tudelft.nl/~gerte/gen2dmraid/ There is also at least one thread about this in the gentoo forums. Here is one for example: http://forums.gentoo.org/viewtopic-t-258981-highlight-dmraid.html I have however since then created my own script which modifies the initrd created by genkernel. I don't use genkernel to make the kernels themselves, but it is the best way in my book to make a initrd in gentoo. One world of advice, regardless which way you choose, be sure to use the newest dmraid version. The older versions had various bugs. My favorite bug was one that setup the raid block size incorrectly while doing mirroring, on two different controlers I use. It isn't funny, when you buy two 400GB drives, and when mirrored, you only see 200GB in linux. Otherwise, you could always go back to using devfs. I think devfs will still be supported for a little while. Maybe by then some gentoo dev will decide to do something about these problems. Regards, Scott -- gentoo-user@gentoo.org mailing list