raid0 using ssd and sdhc on an Acer Aspire One

rolfijn · #1 30th June 2009, 10:09 PM

Hello,

I own an Acer Aspire One netbook. It runs quite all right with Fedora 11. Everything works out of the box after a fresh install. Thanks to all the contributors for this.

The biggest issue i have with this netbook is the slow 8 Gb SSD installed. Despite all the optimisations i've done it's still lagging sometimes. By coincidence i read today on the Debian wiki that it should be possible to create a raid0 (striping) layout with an added SDHC card inserted. Since i had a (4 Gb) SDHC card laying around I thought I might give it a try.

So, I made a backup of all my files and started a new installation. I created a RAID layout with a 4Gb Software RAID partition on the SSD and one on the SDHC and created a ext4 partition on it, to be mounted as "/" . I also created a 100Mb ext3 partition as a "/boot/ partition. Installation seems to go fine.

However, after a reboot i see the Plymouth boot-screen for about a second and then nothing. Rebooting and removing rhgb from the grub commandline reveals the following error:

Code:

    raid0: too few disks (1 of 2) - aborting!
    md: pers->run() failed
    EXT4-fs: unable to read superblock

My take at this is that because of the fact that part of the raidset is placed on the SDHC, the kernel can't handle this because it doesn't have the driver compiled in. Can someone conform this? If so, i suppose I can compile a new kernel. Or would it be possible to insert the module before the rest of the kernel gets loaded, for example by placing it on the "/boot" partition...

Quite a story and quite complicated I'm afraid but perhaps someone knows about this,

Thanks in advance,
Rolf Deenen

PS Here's the partition layout I've created:

Code:

RAID Devices
	/dev/md1		/		ext4		8 Gb
Hard Drives
	/dv/mmcblk0
		/dev/mmcblk0p1	/dev/md1	software raid	3882
	/dev/sda
		/dev/sda1	/dev/md1	software raid	3882
		/dev/sda2	/boot		ext3		75
		/dev/sda3	swap				600
		free		none				3138

rolfijn · #2 2nd July 2009, 09:38 PM

In response to myself: Since there hes been no reaction (no offence) probably because it's very difficult when it can be done at all, i've been looking for another way. I have kept the same partitioning according to the layout above. But the free space has been used for a partition which now holds "/" , together with the space from the swap partition which i deleted; I've added a gigabyte of ram so it won't need to swap. The raid0 device now holds "/home". Success has been mine so far as at least the machine will boot now. I have yet to find out whether the machine works smoother now when it has to do a write operation (in /home off course). I'll try to keep this thread informed.

rolfijn · #3 4th July 2009, 10:27 AM

Well, it was nice while it lasted. Yesterday all worked fine, although i can not say i really noticed a speed difference but the time has been to short to give a definitive verdict. Anyhow, this morning, when i wanted to boot the system it said it could not find the superblock meaning i could not use it any more. Therefore i re-installed fedora again, but now entirely on the internal SSD and I will use the SDHC only for my mp3 collection. To bad....

Regards,
Rolf