Hi There is a quesition on block layout in the raid10 far layout, that I would like to know more about. For 4 drives, and with 2 copies (-n 4 -p n2) I see several possible layouts, 3 of them are, showing the beginning of each raid0 section: Disks: a b c d Layout 1: 1 2 3 4 .............. 4 1 2 3 Layout 2: 1 2 3 4 .............. 3 4 1 2 Layout 3: 1 2 3 4 .............. 2 3 4 1 This gives 3! combinations for double faliure, or ...

There are only two layouts possible here: cyclic, and double-transposition. The first can be summarized in cycle notation <http://en.wikipedia.org/wiki/Cycle_notation> as (abcd), where two letters are adjacent if the extra copy of the first letter is on the same disk as the second letter, and it's assumed the letters wrap around in the parentheses (so the extra copy of d is on the same disk as a). The second is (ab)(cd). So for instance, your example 1 is (1432), example 2 is (13)(24), and ...

On Tue, 11 May 2010 18:22:58 -0400 A grad student! You must be over educated: The conclusion stated in question 20 is correct if you are considering the 'near' layout, though the reasoning is foggy and doesn't generalise to the 'far' or 'offset' layout. With a 'near 2' layout on 4 drives, the blocks are: 0 0 1 1 2 2 3 3 which looks like striping across mirrored pairs, but that is really just a coincidence. On 5 drives it would look like: 0 0 1 1 2 2 3 3 4 ...

hello , i m using mdadm - v2.6.7.1 . when I m creating a raid array of 4 disk using command mdadm --create --chunk=64 --level=0 --raid-devices=4 /dev/md99 /dev/sda /dev/sdb /dev/sdc /dev/sdd in dev directory of my PC I m getting md99 device and along with this md_d99 . So I m not able understand what is this md_d99 ? this thing was not happening previously in previous versions of mdadm . another issue if i reboot the PC also it shd keep active the md99 array , but it is not ...

What tool other than telnet do you use to open an interactive socket to an arbitrary port? -- Bill Davidsen <davidsen@tmr.com> "We can't solve today's problems by using the same thinking we used in creating them." - Einstein --

http://www.sysresccd.org is nice, it has mdadm and ssh, no telnet and ftp, but who needs those nowadays :P -- Luca Berra -- bluca@comedia.it Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \ --

I'm pretty sure it has been reported more than once. Google brings up a ton of responses when one searches for the error produced when udev tries to upgrade and can't because of the old kernel. I don't recall what the error is, exactly, because I first ran into it several months ago. Note it is only encountered when trying to upgrade from "Lenny" to "Squeeze", not when loading "Squeeze" directly, but then "Squeeze" is still a testing distro. It hasn't been released, yet, and probably won't ...

On Mon, 10 May 2010 12:59:33 -0400 Maybe .... For backwards compatibility, the event counts in all the devices in an array must not differ by more than 1. And if the information in the superblocks is different, then the event counts must be different to ensure that the current information is used when the array is restarted. Consequently, if the event counts are uniform across an array it is safe to just mark the superblocks on active drives as 'dirty' leaving spare drives alone. To ...

On Tue, 11 May 2010 11:06:48 -0700 No thanks, the link below is good enough. That patch is now in my for-next branch and will go for-linus in 2.6.whatevercomesnext. I normally stick that sort of thing somewhere in my stack before replying Maybe we should just get rid of the BUG_ON?? Let's set how it goes once this patch is really in. Thanks, NeilBrown --