Adding more swapfiles

Adding more swapfiles

If you want to add a swapfile, perhaps you should read swap files first.  This article deals with adding a additional swapfile after adding your first swapfile.  So if you already have a swap file (and I’m not talking about a swap partition), and you want to add another, then this is the article for you.

Out of swap space again

I need yet more swap.  So I went and created a new swap file:

# dd if=/dev/zero of=/usr2/swapfile bs=15m count=20
10+0 records in
20+0 records out
314572800 bytes transferred in 40.594 secs (387462 bytes/sec)

Note that the above should have give you a 300Mb file (bs=15m, count=20 or 15Mx20 = 300Mb).  Enjoy.

Creating a new device

Before we can use this swapfile, we need to create a new vnconfig device.  Here’s how I did that:

# cd /dev
# ./MAKEDEV vn1

Telling vnconfig about the new swapfile

Before I started this article, my /etc/vntab contained this:

/dev/vn0c /usr4/swapfile swap

After adding the new device, here’s what the config file looked like:

/dev/vn0c /usr4/swapfile swap
/dev/vn1c /usr2/swapfile swap

My thanks to Glenn Johnson for his advice on the MAKEDEV and the config file.

Restarting vnconfig

Actually, I just rebooted to check some NFS issues, but I suspect the following would be sufficient:

vnconfig -ae

The results

Now I have this as swap space:

$ swapinfo
Device          1K-blocks     Used    Avail Capacity  Type
/dev/ad0s1b         70776     2128    68648     3%    Interleaved
/dev/rvn0c         153472     2088   151384     1%    Interleaved
/dev/rvn1c         307072     2248   304824     1%    Interleaved
Total              531320     6464   524856     1%

We’ll see how that goes.