From: Derek R. M. <de...@et...> - 2005-10-07 18:05:14
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How can I use over 16 UBD devices? I have read in the mailing lists that you can create partitions: brw-r--r-- 1 root root 98, 1 Oct 7 12:52 /dev/ubd0p1 However; I cannot mount the above device while UML is booting. Can someone provide me with some direction? -- Derek R. Meiresonne |
From: Blaisorblade <bla...@ya...> - 2005-10-07 18:16:46
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On Friday 07 October 2005 20:04, Derek R. Meiresonne wrote: > How can I use over 16 UBD devices? I have read in the mailing lists that > you can create partitions: > brw-r--r-- 1 root root 98, 1 Oct 7 12:52 /dev/ubd0p1 > However; I cannot mount the above device while UML is booting. Can you explain what you mean? You can put /dev/ubd0p1 in /etc/fstab without problem. You can even make Uml boot from it, by adding rootfs=/dev/ubda1 * or if the kernel doesn't understand that, add root=98:1, i.e. with major:minor; note that IIRC, those numbers are Hex, so you don't want to use root=98:10 but instead root=98:a. * ubd devices also support a Ide-like syntax, with letters, since when they support partitions; nobody ever used /dev/ubd0p1, even it that's a general convention, so beware. > Can > someone provide me with some direction? Wait a moment. You can attach 8 different ubd devices IIRC, i.e. host files, and that is trivial to raise to 16 (just change a define), and could even be changed to more (it's just a matter of allocating some new major number - must talk with upstream people to decide which one to use, but it's otherwise ok). Each host file can be partitioned. And you can mount it via /etc/fstab. But you can't attach different partitions to different host files. Actually you could use DeviceMapper to concat the files together, after loop-mounting them, but it's not trivial to do, and you'd also have to write a fictious partition table matching the host files. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB http://mail.yahoo.it |
From: Derek R. M. <de...@et...> - 2005-10-07 18:40:04
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> "You can attach 8 different ubd devices IIRC, i.e. host files, and that trivial to raise to 16 (just change a define)" I dont understand this part. I have raised MAX_DEV in ubd_kern.c to 60. But that is not the problem. issue is the limit of 16... partitions? Derek R. Meiresonne eTecc Communications, Inc. www.eTecc.com Blaisorblade wrote: > On Friday 07 October 2005 20:04, Derek R. Meiresonne wrote: > >>How can I use over 16 UBD devices? I have read in the mailing lists that >>you can create partitions: > > >>brw-r--r-- 1 root root 98, 1 Oct 7 12:52 /dev/ubd0p1 > > >>However; I cannot mount the above device while UML is booting. > > Can you explain what you mean? You can put /dev/ubd0p1 in /etc/fstab without > problem. > > You can even make Uml boot from it, by adding > > rootfs=/dev/ubda1 > * > or if the kernel doesn't understand that, add > root=98:1, i.e. with major:minor; note that IIRC, those numbers are Hex, so > you don't want to use root=98:10 but instead root=98:a. > > * ubd devices also support a Ide-like syntax, with letters, since when they > support partitions; nobody ever used /dev/ubd0p1, even it that's a general > convention, so beware. > >>Can >>someone provide me with some direction? > > Wait a moment. > > You can attach 8 different ubd devices IIRC, i.e. host files, and that is > trivial to raise to 16 (just change a define), and could even be changed to > more (it's just a matter of allocating some new major number - must talk with > upstream people to decide which one to use, but it's otherwise ok). > > Each host file can be partitioned. And you can mount it via /etc/fstab. But > you can't attach different partitions to different host files. > > Actually you could use DeviceMapper to concat the files together, after > loop-mounting them, but it's not trivial to do, and you'd also have to write > a fictious partition table matching the host files. |
From: Blaisorblade <bla...@ya...> - 2005-10-09 19:08:34
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On Friday 07 October 2005 20:39, Derek R. Meiresonne wrote: > > "You can attach 8 different ubd devices IIRC, i.e. host files, and > > that trivial to raise to 16 (just change a define)" > I dont understand this part. I have raised MAX_DEV in ubd_kern.c to 60. More than 16 is likely to create problems, I guess (we should allocate more majors probably) > But that is not the problem. issue is the limit of 16... partitions? Ah, ok, that's different. Just increase UBD_SHIFT (the number of partitions is 2 ^ UBD_SHIFT). But you'll need to recreate device nodes... and that's why the thing is not so easy to change. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB http://mail.yahoo.it |