Op 22-01-16 om 23:27 schreef Phil Turmel: > On 01/22/2016 04:55 PM, Paul van der Vlis wrote: >> Hello, >> >> I want to put bigger disks into my server. What I want to do is replace >> the first disk, rebuild the raid, replace the second disk, rebuild the >> raid. The machine has two disks, sda and sdb. >> >> But, when I replace a disk, it gets a new device name. E.g. /dev/sdb >> becomes /dev/sdc. After a reboot it's good again, but I prefer not to >> reboot this machine! >> >> Is there a way to get the correct device name? > > No. Device names are assigned in the order they are encountered after > boot, and that order is not guaranteed by the kernel. You should never > depend on those names. > > When a device name is fully disconnected, modern kernels will recycle > the name at the next opportunity. Correct, I see that with USB-sticks. > You must be using a hotplug-enabled > driver. For most motherboards, turning on "AHCI" mode in the BIOS on > those sata ports is all you need. I have that. I am using an Intel chipset: 00:1f.2 SATA controller: Intel Corporation 6 Series/C200 Series Chipset Family SATA AHCI Controller (rev 05) >> When not: >> Is it maybe an idea too add the wrong device name to the md-device? >> mdadm /dev/md0 -a /dev/sdc1 >> Then replace /dev/sda what becomes /dev/sdd: >> mdadm /dev/md0 -a /dev/sdd1 >> Then restore grub on both disks (with "--recheck" ??) >> But what will happen after a reboot later? Will the md-device be >> restored with the old names? > > MD stores signatures in the devices it uses that identify them for later > assembly. It does not depend on the device name, though it is recorded > in the superblock as a "last connected as" kind of indicator. So I can do it as described above? > In general, you should not rely on device names in your system > configuration. UUIDs and filesystem labels were implemented > specifically to avoid this problem. So far I know I cannot configure anywhere a disk UUID or a filesytem label to a MD-device. It feels wrong when I add /dev/sdc1 to the raid, when the name is normally /dev/sdb1. But maybe it's no problem, because the device name is not impartant while booting from an MD-device. With regards, Paul van der VLis. -- Paul van der Vlis Linux systeembeheer Groningen https://www.vandervlis.nl/ -- 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
