[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: bootable RAID, number of member disks limitation
|
From: |
Chris Murphy |
|
Subject: |
Re: bootable RAID, number of member disks limitation |
|
Date: |
Fri, 4 Jan 2013 00:42:57 -0700 |
On Jan 3, 2013, at 3:00 PM, Vladimir 'φ-coder/phcoder' Serbinenko
<address@hidden> wrote:
> GRUB has no limitation on number on devices other than free memory to
> hold structures and 2^32 for IDs. If there is any other limit it's a bug
> and please file a bug report with the images in question (no need to
> install, just use grub-fstest) However BIOS limits the number of disks
> that can be accessed. Theoretically there could be up to 128 (or 256 if
> you use floppy numbers as well) accessible through BIOS. The convention
> is to use only 16 possible IDs for HDD (0x80-0x8f). In practice many
> BIOSes are limited to less (8 is usual limit).
I'm totally unclear on how to use grub-fstest.
Should ls at grub rescue report all attached devices?
With single disk btrfs only (no md RAID), at a grub command prompt, ls reports
(hd0) (hd0,msdos1) (hd1) (hd2) (hd3)
Yet there are 11 devices attached. This is VirtualBox, so this very well may be
a vbox limitation. I haven't tried it with KVM's SEABIOS yet.
With md RAID only (no Btrfs), ls reports:
(md/root) (hd0) (hd0,msdos1) (hd1) (hd1,msdos1) (hd2) (hd1,msdos2)
Chris Murphy