My original question, interleaved with a summary of responses :
>> I need to increase the active swap partition /dev/rdsk/c0t3d0s1 (2.5.1
>> boot disk) as I have undersized it during install.
>> I do not have any spare space on any other volumes, so I can't easily
>> add another swap file.
>> Looking at the partition information on c0t3d0 I have decided to
>> decrease the size of c0t3d0s3 (the next contiguous partition, used for
>> /export/home) and add the extra cylinders to s1 for swap.
>> This is what I thought I'd do, but not entirely sure if this is correct
>> (which is where you guys come in !) :
>> back up /export/home and take server (SS20 192Mb RAM) to single user
>> (perhaps) issue swap -d /dev/dsk/c0t3d0s1 to delete the swap space.
>> Reformatted the disk, increasing slice 1 accordingly and adjusting
>> beginning of slice 3 etc.
>> newfs c0t3d0s3 for /export/home.
The general concensus was that the above was fundamentally correct...
>> Do I need to do anything with c0t3d0s1 if i've left /etc/vfstab
>> intact ? Will swap automatically get adjusted after I reboot ?
Yes, swap will get adjusted if you leave /etc/vfstab as it is.
>> Also, IF i did get an extra disk, could I create a partition on it for
>> swap and just add a swap type entry in /etc/vfstab for that partition?
Yes, this is also perferable to a single swap partition. The OS will
interleave swap disk accesses across multiple partitions.
>> Where does the mkfile command fit into all this ?
This is what caused my confusion in the first place....the old swap
partition vs swap file chestnut.....
Here's what David Thorburn-Gundlach <email@example.com> says......
"Aha! This explains all of the above :-) mkfile makes a file (clever, I
know) of a specified size, typically for use as an additional swap device.
Since you mentioned /etc/vfstab above, I'll assume you're running Solaris
and run down the steps for you:
- calculate desired (and available) additional swap space (let's assume
- create a subdirectory under /export/home for your swap file, if you wish
chmod 700 /export/home/.swapfiles
- create a 64M file for use as swap space
(I chose the name in case you later make a 32M or 128M swap file, or a
second 64M swap file. It's actually immaterial.)
- start using the swap space
/usr/sbin/swap -a /export/home/.swapfiles/064m-1
- make the addition permanent
echo "/export/home/.swapfiles/064m-1 - - swap - no -" >> /etc/vfstab
- enjoy your new swap space
Matthew Stier <Matthew.Stier@tddny.fujitsu.com> says.....
"The easiest, fastest, most flexible t hing to do, is to create a swap
In a filesystem you can have available space, use 'mkfile' to create a file
of the size of swap space you want to add, then use 'swap -a' to add that
space to to swap.
The performance penalty, is typically < 1%"
Opinion was divided between adding a swap file or repartitioning and
increasing the swap partition. Performance issues are, it appears,
negligible between the two. There are plenty of references to this in the
Archives (which I couldn't access at the time of my posting this question).
In the end, I went for repartitioning the disk and restoring /export/home
after rebooting. All went OK.
Many thanks to :
David Thorburn-Gundlach <firstname.lastname@example.org>
Benjamin Cline <email@example.com>
Rich Casto <firstname.lastname@example.org>
Brion Leary <email@example.com>
Matthew Stier <Matthew.Stier@tddny.fujitsu.com>
Glenn Satchell - Uniq Professional Services <Glenn.Satchell@uniq.com.au
Mariel Feder <firstname.lastname@example.org>
for their invaluable help.
Tel: UK+(0)171 378 5775
Securities and Futures Authority
This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:12:06 CDT