Messages in this thread | | | Subject | Re: support of older compilers [u] | From | "Martin Schlemmer [c]" <> | Date | Sat, 06 Nov 2004 00:37:26 +0200 |
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On Fri, 2004-11-05 at 22:59 +0100, Grzegorz Kulewski wrote: > > The kernel does do more these days than it did in '95. But 6 times more? I > > dunno.. > > Can't we remove ramfs for a good start? Everyone should use tmpfs instead > and some stupid distributions (I will not tell their names) try to mount > ramfs on /dev (udev) and that leads to very stupid panic if you will > write for example: > > dd if=/dev/evms/sda5 of=/dev/sda17 bs=1024 > > instead of "of=/dev/evms/sda17". > > Explanation (if anybody needs one): > Kernel can't create more partition devices than 15 for SCSI and SATA disks > because of lack of minor numbers. So I am using evms to create these > devices. So I should use /dev/evms/sda* for these partitions. And if I > will not remember to do so then I will get oom panic very shortly because > ramfs is not limited (in contrary to tmpfs). > > And this kind of stupid mistake can happen. It happened to me 3 times in a > row before I started to debug what is wrong with this kernel. > > [BTW. Does somebody know how to tell the kernel that I do not want > /dev/sda[0-9]* files (but I do want /dev/hda files) created == I do not > want kernel partition driver to touch this particular device?] >
So basically /dev/sda* have major of scsi, and /dev/evms/sda* have major of evms, and you end up using the wrong nodes? This sounds more like a udev-ruleset problem (not something that will be easy to get right with a generic one I imagine), rather than anything remotely to do with ramfs. If you changed the scripts to use tmpfs rather, you would have gotten the same result.
Now I do not know evms, so you are on your own there, but here is my rules for dm and a similar issue:
--------- nosferatu linux-2.6-bk # cat /etc/udev/rules.d/30-sda.rules KERNEL="sda[0-9]*", NAME="" nosferatu linux-2.6-bk # cat /etc/udev/rules.d/40-dm.rules KERNEL="dm-[0-9]*", PROGRAM="/sbin/devmap_name %M %m", NAME="mapper/%c", SYMLINK="%c" nosferatu linux-2.6-bk #
---------
(note that they should be before all the others if you only have one rule file)
So basically for the real scsi devices (you could add a BUS="scsi" to make sure I guess) matching 'sda[0-9]*' no node will be created, and I get my /dev/mapper/* nodes, with a symlink in /dev/ making things easier.
you could have a rule catching all evms devices, and then add the /dev/sda* symlinks, perhaps like so:
-------- KERNEL="evms/sda[0-9]*", SYMLINK="sda%n" --------
Note that I do not know if a rule was needed to get the nodes in /dev/evms/ in the first place (due to my admitted lack of evms knowledge above), so you might have to modify an existing rule ...
-- Martin Schlemmer
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