News Group Posts

swapping a hard drive, hot swap, raid, divvy,

badtrk

From: Bela Lubkin <belal@sco.com>
Subject: Re: Swapping a hd in 5.0.6
Date: Thu, 14 Nov 2002 09:33:41 GMT
References: <20021108112935.A9421@egps.egps.com>
<20021109164949.05596@tegan.com>
<20021109193812.A24538@egps.egps.com>
<20021109204029.17968@tegan.com>
<20021110164846.A1171@egps.egps.com> 

Nachman Yaakov Ziskind wrote:

> So, last night, while working from home, feeling dreary, pondering Tom's
> admonition to make sure I was looking at the right drive (and darn it, I WAS
> looking at the right drive), and then I saw it:
> 
> Current Hard Disk Drive: /dev/rdsk/3s0
> 
>         +-------------+----------+-----------+---------+---------+---------+
>         | Partition   | Status   | Type      |   Start |     End |    Size |
>         +-------------+----------+-----------+---------+---------+---------+
>         | 1           | Active   | UNIX      |       1 |  281774 |  281774 |
>         +-------------+----------+-----------+---------+---------+---------+
> 
> Total disk size: 2258025 tracks (256 reserved for masterboot and diagnostics)
> 
> At which point, I noticed the "Total disk size:" DUH! Perhaps the 'tracks' it
> is counting is not the same as the Start/End figures? I did some feverish
> reading on the fdisk man page and decided that, no, tracks are tracks, and
> fdisk is only looking at 12% of the drive. I selected "Use Entire
> Disk for UNIX", and (after a scary warning) got: 
> 
>         | 1           | Active   | UNIX      |       1 | 2257769 | 2257769 |

During the hot-swap episode, you caused a copy of the old disk's fdisk
table to be written to the new disk.  You did _not_ do anything to
overwrite the new disk's proper geometry.  fdisk tables are expressed in
linear block numbers; in effect you laid down a table that gave
partition #1 exactly as much space as it had on the old disk (and thus
only a fraction of the new disk).

(Actually, for SCSI disks, OpenServer only cares about the
"sectors/track" and "heads" geometry parameters; it determines the
"tracks" parameter by dividing total disk size by those two.  So you
could not have "damaged" the total disk size by writing a wrong
parameter table.)

> Which looked MUCH better. So, letting the dice roll, I ran divvy, and got the
> same division table as before, with one small difference:
> 
> 71111722 1K blocks for divisions, 8001 1K blocks reserved for the system
> 
> Which I picked up on right away. :-) I thought I'd just expand the last block
> of the first filesystem to 71111722, umount and mount, and away I'd go. 
> 
> But no, the filesystem stayed at 9gig in df -vk.

Changing the boundaries of an HTFS filesystem doesn't have any effect on
its internal structures, which tell it that it ends at the old boundary.
If you have a house and you buy the vacant lot next door, it doesn't
make your house any bigger -- you would have to build an addition or rip
it down and build a bigger one.  John DuBois has a utility for building
that addition, at ftp://ftp.armory.com/pub/admin/chfssize (danger: this
is a utility for People Who Know What They Are Doing And Have Made Good
Backups).  Otherwise you tear down and rebuild, as you did.

>                                                  After more head scratching, I
> decided to remove all the first division entirely, and reinput the numbers.

What you wanted was divvy's "c[reate]     Create a new file system on
this division." choice.  You probably used that, since changing
boundaries does not automatically prompt divvy to create a filesystem.
It didn't occur to you to just use "c[reate]", but it was obvious to you
that after moving the boundaries you needed to do that.

> Much happier! Divvy declared:
> 
> Making Filesystems
> 
> and mkfs sat there for a most satisfying five or ten minutes, and I was now up
> to 73gig, Woo-hoo!

Yay!

>Bela<
 

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