No, the question was not related to RAID0+1. I my opinion, RAID0+1 would be evil! RAID1+0 or md's RAID10 would be much better. Guy > -----Original Message----- > From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid- > owner@xxxxxxxxxxxxxxx] On Behalf Of Andrew Rechenberg Lists > Sent: Monday, April 25, 2005 4:05 PM > To: linux-raid@xxxxxxxxxxxxxxx > Subject: RE: raid 10 or 1+0 ? > > The subject of the mail should be "raid 10 or 0+1" I believe :) > > According to acnc.com: > > http://www.acnc.com/04_01_10.html > > "RAID 10 is implemented as a striped array whose segments are RAID 1 > arrays " > > http://www.acnc.com/04_01_0_1.html > > "RAID 0+1 is implemented as a mirrored array whose segments are RAID 0 > arrays" > > If a drive were to fail in a RAID0+1, what you are left with is > essentially one RAID0 array. > > You want to use RAID10 if you need high performance and very good fault > tolerance. The disadvantage is that you end up with half of the > available raw space as useable. > > I've never seen nor tried a "/" file system on RAID10 or RAID0+1. What > I usually hear recommended is /boot and or / on RAID1 and then if you > need better performance for a database or other application, then create > a /data partition or something of the sort on a separate RAID10 array > that is on different disk spindles. > > Here is our configuration: > > /: RAID1 > /backup: RAID0 disk backup staging area > /data: LVM on a 56 SCSI disk SW RAID10 array > > > HTH, > Andy. > > > > -----Original Message----- > > From: linux-raid-owner@xxxxxxxxxxxxxxx > > [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of Andre Noll > > Sent: Sunday, April 24, 2005 9:54 AM > > To: linux-raid@xxxxxxxxxxxxxxx > > Subject: Re: raid 10 or 1+0 ? > > > > On Sat, 23 Apr 2005 12:21:17 -0400 you wrote in > > local.lists.linux-raid: > > > > > Maybe we need some success stories for RAID10 and RAID1+0 > > mounted on "/". > > > > I have such a setup up and running for quite some time now: > > > > cat /proc/mdstat > > Personalities : [raid0] [raid1] > > md3 : active raid0 md1[0] md2[1] > > 156247808 blocks 64k chunks > > > > md2 : active raid1 hda2[0] hdk2[1] > > 78123968 blocks [2/2] [UU] > > > > md1 : active raid1 hdc2[0] hdg2[1] > > 78123968 blocks [2/2] [UU] > > > > md0 : active raid1 hdc1[2] hda1[3] hdk1[1] hdg1[0] > > 49280 blocks [4/4] [UUUU] > > > > My roottfs is on a lv. The corresponding vg is made from md3. > > > > This works if you do not rely on the kernel to assemble your > > array but use an initrd to achieve this. > > > > Just use something like this in your linuxrc, right after > > creating the device nodes (if you use udev): > > > > if test -e /proc/mdstat; then > > log "scanning for multi disk devices" > > echo "DEVICE /dev/hd[a-z] /dev/sd[a-z] > > /dev/md[0-9]" > /etc/mdadm.conf > > mdadm --examine --scan --config=/etc/mdadm.conf \ > > >> /etc/mdadm.conf > > mdadm --assemble --scan > > fi > > > > if test -c /dev/mapper/control; then > > log "setting up lvm" > > vgscan --mknodes > > vgchange -a y > > fi > > > > > > BTW, you should definitively use striped mirrors rather than > > mirrored stripes. > > > > However, note that you can not boot from a striped mirror. > > That is, you need a tiny partition, preferably at the > > beginning of your discs, to store the kernel image and the > > initrd, but not the rootfs. You can make it a raid1 over all > > disks, like my md0 above, and use lilo to write a mbr to > > _all_ discs. That way you can shuffle around your discs and > > your system will still boot. > > > > More details on request ;) > > Andre > > -- > > Andre Noll, http://www.mathematik.tu-darmstadt.de/~noll > > > > - > > To unsubscribe from this list: send the line "unsubscribe > > linux-raid" in the body of a message to > > majordomo@xxxxxxxxxxxxxxx More majordomo info at > > http://vger.kernel.org/majordomo-info.html > > > Confidentiality Notice: This e-mail message including attachments, if any, > is intended > only for the person or entity to which it is addressed and may contain > confidential > and/or privileged material. Any unauthorized review, use, disclosure or > distribution > is prohibited. If you are not the intended recipient, please contact the > sender by reply > e-mail and destroy all copies of the original message. If you are the > intended recipient, > but do not wish to receive communications through this medium, please so > advise the > sender immediately. > > > - > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
