Re: MD does not wait for drives on start-up with kernels 3.8+

[NeilBrown <neilb@suse.de>]

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On Mon, 15 Apr 2013 14:45:30 +0600 Roman Mamedov <rm@romanrm.ru> wrote:

> On Sun, 31 Mar 2013 09:36:30 +0400
> CoolCold <coolthecold@gmail.com> wrote:
> 
> > In similar situation (but on 2.6.2x kernels i AFAIR, with scsi drives)
> > I've used rootdelay param -
> > http://lists.debian.org/debian-user/2012/01/msg00748.html to make md
> > assembly succeed. Hope this will help you too.
> 
> Thanks, rootdelay=10 seems to have solved the problem.
> 
> ...
> [    3.860538] scsi 12:0:0:0: Direct-Access     ATA      Hitachi HDS5C302 ML6O PQ: 0 ANSI: 5
> [    3.860716] sd 12:0:0:0: Attached scsi generic sg8 type 0
> [    3.860879] sd 12:0:0:0: [sdi] 3907029168 512-byte logical blocks: (2.00 TB/1.81 TiB)
> [    3.860906] sd 12:0:0:0: [sdi] Write Protect is off
> [    3.860908] sd 12:0:0:0: [sdi] Mode Sense: 00 3a 00 00
> [    3.860920] sd 12:0:0:0: [sdi] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
> [    3.872747]  sdi: sdi1 sdi2 sdi3
> [    3.873014] sd 12:0:0:0: [sdi] Attached SCSI disk
> [    4.144402] scsi 14:0:0:0: Direct-Access     ChipsBnk   Multi-Reader   4082 PQ: 0 ANSI: 2
> [    4.145294] sd 14:0:0:0: Attached scsi generic sg9 type 0
> [    4.147579] sd 14:0:0:0: [sdj] Attached SCSI removable disk
> [    4.179650] ata14: SATA link down (SStatus 0 SControl 300)
> [    4.601802] hid-generic 0003:051D:0002.0001: hiddev0,hidraw0: USB HID v1.10 Device [American Power Conversion Back-UPS RS 500 FW:30.j5.I USB FW:j5] on usb-0000:00:12.0-3/input0
> [    4.601987] input: Logitech HID compliant keyboard as /devices/pci0000:00/0000:00:12.2/usb1/1-6/1-6.1/1-6.1:1.0/input/input2
> [    4.602051] hid-generic 0003:046D:C30E.0002: input,hidraw1: USB HID v1.10 Keyboard [Logitech HID compliant keyboard] on usb-0000:00:12.2-6.1/input0
> [    4.606121] input: Logitech HID compliant keyboard as /devices/pci0000:00/0000:00:12.2/usb1/1-6/1-6.1/1-6.1:1.1/input/input3
> [    4.606647] hid-generic 0003:046D:C30E.0003: input,hidraw2: USB HID v1.10 Device [Logitech HID compliant keyboard] on usb-0000:00:12.2-6.1/input1
> [   12.537344] nbd: registered device at major 43
> [   12.599970] md: md0 stopped.
> [   12.603855] md: bind<sde3>
> [   12.604029] md: bind<sda3>
> [   12.604139] md: bind<sdi3>
> [   12.604290] md: bind<sdc3>
> [   12.604618] md: bind<sdb3>
> [   12.604779] md: bind<sdd3>
> [   12.604982] md: bind<sdh3>
> ...
> 
> This was NOT required on any of the previous kernels, so I wonder why all of
> sudden with the 3.8+ kernels my system needs an extra "crutch" just to keep
> starting up properly.
> 
> 

This is almost certainly not directly related to the kernel.  It seems clear
that some change in the kernel has resulted in the difference, but it is
probably indirect and really a bug elsewhere.

What distro are you using?  Is systemd in use?

systemd runs lots of things in parallel which is theoretically good, but
tends to expose races.

Possibly inserting "udevadm settle" somewhere before "mdadm" runs - or maybe
even "udevadm trigger ; udevadm settle" would do it.
This would need to be in the initrd of course.

NeilBrown

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