| 1 |
I haven't used a swap partition on any of my systems (intel celeron, |
| 2 |
p3, amd64, intel xeon) for over... what... 10 years? |
| 3 |
Swapfiles only, and sometimes I don't even mount the swap. Although I |
| 4 |
have never removed support for any kind of swap from my kernel. |
| 5 |
|
| 6 |
|
| 7 |
dd if=/dev/zero of=/path/to/swapfile bs=1M count=1024 |
| 8 |
mkswap /path/to/swapfile |
| 9 |
swapon /path/to/swapfile |
| 10 |
(btw, I like to put the swap file in /root or /boot, but that's my |
| 11 |
pref, on space constrained PC, i would put a swapfile on every drive |
| 12 |
to distribute it). |
| 13 |
|
| 14 |
|
| 15 |
I don't have access to my box to confirm but I think /etc/fstab would |
| 16 |
be setup the same as normal swap except with the file path instead of |
| 17 |
the device partition. |
| 18 |
|
| 19 |
Except for issue pointed out by Paul about hibernation, dd line above |
| 20 |
takes care of non-sparsity. As for security, having a swap is less |
| 21 |
secure than having none: a malicious persion could extract |
| 22 |
information from programs memory which was swapped (ie, like the |
| 23 |
decripted information "for your eyes only"). |
| 24 |
|
| 25 |
Having no swap at all was a problem on small systems with little RAM |
| 26 |
when emerging big stuff (boost failed all the time on a pc with |
| 27 |
256mb). |
| 28 |
|
| 29 |
Resizing swap "on-the-fly" with swapfiles: |
| 30 |
And on HDD-space constrained system, i used to have several |
| 31 |
swapfiles that I created and deleted in the manner above, that I named |
| 32 |
swapfile-256, swapfile-512, etc... A smooth "upgrade of swap |
| 33 |
on-the-fly" was done this way: say I had 256 swapped on, I could swap |
| 34 |
on a new 512 (768 total at moment, all data still on 256mb file), then |
| 35 |
swapoff the 256 (takes a bit of time for swap data to move over), |
| 36 |
delete the 256. Downgrade can be done in the same manner. "swapon |
| 37 |
-s" (status) will be a good friend of yours now. |
| 38 |
|
| 39 |
Good luck! |
| 40 |
|
| 41 |
Simon |
| 42 |
|
| 43 |
|
| 44 |
On Wed, May 2, 2012 at 2:53 PM, walt <w41ter@×××××.com> wrote: |
| 45 |
> I have two machines with 4GB of ram and I've never seen either one use |
| 46 |
> swapspace (yet) so I'm thinking I could delete my swap partitions and |
| 47 |
> substitute a much smaller swapfile -- if it's safe. |
| 48 |
> |
| 49 |
> Any downside to using a swap file instead of a swap partition, maybe |
| 50 |
> depending on which filesystem you use, or something? Security holes? |
| 51 |
> Any horror stories out there? |
| 52 |
> |
| 53 |
> |
Archives