|
OpenBSD General Other questions regarding OpenBSD which do not fit in any of the categories below. |
|
Thread Tools | Display Modes |
|
|||
Partitioning schemes
What is the situation with partitioning in OpenBSD now? At least formerly, I think, OpenBSD required non-OpenBSD MBR partitions to be described in the OpenBSD MBR partition's disklabel, which I think is complete madness and an example of bad design. In my opinion, sub-partitioning schemes should not refer to data outside of the subdivided MBR partition, and they should not use absolute disk addresses. They should use offsets relative to the subdivided partition's address.
https://web.archive.org/web/20151121...foreignfsafter And what is the situation with OpenBSD's GPT support? Does OpenBSD still require disklabels or can it use GPT partitions directly? Can OpenBSD 5.9 use MBR partitions without having them described in a disklabel? |
|
|||
Can OpenBSD 5.9 be installed onto a GPT disk without a disklabel at all, as there are more possible codes for partition types? I think FreeBSD doesn't need disklabels on GPT disks when using UFS.
|
|
|||
I mean, will it work if no actual disklabel exists on the disk? Just GPT partitions with the FFS file system.
|
|
||||
I don't think so, because an MBR/GPT OpenBSD partition is not a filesystem. It's a collection of one or more filesystems, managed via a disklabel. On the six or so MBR (or GPT) architectures, there are two distinct layers of partitioning. On the 11 or so non-MBR architectures, there is only a single layer of partitioning.
Virtual disklabels are allocated only to recognized foreign filesystems (FAT, ext, NTFS, CD9660, ...). |
|
|||
I am curious where disklabel information is stored on hard driver.
Example: MBR is 512 bytes long and starts at the (CHS – 0, 0, 1). Where is disklabel's information stored? If I wipe/override FFS filesystem does these information will persist, because it is stored outside FFS filesystem? I am particularly interested in amd64 architecture. |
|
||||
It varies by architecture, so I'm glad you specified.
On amd64, it uses the second sector of the OpenBSD MBR/GPT partition (partition type A6), or the second sector of the drive if no MBR or GPT is defined. For clarity, if the partition starts at LBA 64, the disklabel is stored in LBA 65, and if there is no MBR or GPT defined in LBA 0, the disklabel is stored in LBA 1. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Partitioning a Backup Disk? | Mantazz | FreeBSD Installation and Upgrading | 2 | 29th April 2012 07:34 PM |
MBR GPT hybrid partitioning | J65nko | FreeBSD Installation and Upgrading | 2 | 16th November 2011 09:37 AM |
CAPTCHA schemes still easy to bypass | J65nko | News | 8 | 7th November 2011 08:09 PM |
Partitioning for web/mailserver? | DrKrall | OpenBSD Installation and Upgrading | 3 | 20th November 2009 01:14 PM |
Is partitioning still important in installation? | Mantazz | FreeBSD Installation and Upgrading | 14 | 16th January 2009 08:35 AM |