[CentOS] Old Small Box

Ross Walker rswwalker at gmail.com
Thu Jan 22 22:19:13 UTC 2009


On Thu, Jan 22, 2009 at 2:58 PM, Robert Moskowitz <rgm at htt-consult.com> wrote:
> Ross Walker wrote:
>> On Jan 22, 2009, at 11:39 AM, Robert Moskowitz <rgm at htt-consult.com>
>> wrote:
>>
>>
>>> Kai Schaetzl wrote:
>>>
>>>> Ralph Angenendt wrote on Thu, 22 Jan 2009 10:31:20 +0100:
>>>>
>>>>
>>>>
>>>>> You need a combined(!) 768MB of RAM and Swap to successfully install
>>>>> CentOS 5.2 (see the release notes).
>>>>>
>>>>>
>>>> in graphics mode.
>>>>
>>> And really it is a performance question as long as you have 256M of
>>> real
>>> memory, the rest swap.  Since I always make my swap > 2xRAM, I am
>>> always
>>> installing on a system with at least 768Mb combined.
>>>
>>> I do not like the DIsk Druid default of putting the swap drive into
>>> the
>>> LVM partition.  I always redo the partitions so that swap is its own
>>> partition.
>>>
>>
>> Why is that? Old school habit or is there a real benefit?
>>
>
> It just feels wrong in so many ways.
>
> Why is /boot its own partition and not swap? I suspend to swap, so swap
> has to be as accessible as /boot?

Well the only reason /boot isn't possible in LVM is because grub can't
of yet handle reading LVM volumes. As soon as it can though, there will
be no need for a separate /boot.

> Am I going to enlarge swap at some point using LVM tools? Or shrink it?
> Can you even do that with a swap partition in LVM? So what ARE the
> values of swap in LVM? One less partition, I would think if you are
> going duo boot. But if not, again, where is the beef?

You can enlarge or shrink it if you want, remove it from swap first, but
many people just create another LV and add it to the mix.

I think the biggest benefit to swap on LVM is when working with software
RAID1 on the main disks, where you don't need to worry about creating
a special MD just for swap, md0 for /boot, md1 for LVM.

Not really a beef, in my books though it's added partitioning and
potentially wasted space, but disks are big these days, so what.

>> Swap performance should be equally good whether it be raw disk, raw
>> partition, LVM logical volume or even a flat file on today's kernels,
>> but maybe there is something I am unaware of.


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