Re: stripe swapping
hi ya knud
there is almost no point to using swap space....
let alone making it redundant or ha...
if you have 640Mb of ram.... how big is your biggest
appp andits associated data ??? if over 640Mb...than yeah
you need swap
and some motherboards supports 4Gb of ram...
--------
for your partition issues... its a poor argument for why
you need swap space....
with two identical drives...and performance is an issue
...yes....raid stripping cane make READS faster....but
writes will be slower.... how many times do you write
vs reading it back ???
for number or partitions....
my own preference is..
/ 64mb
/tmp 129Mb or something
/var 512Mb or something larger for large web/email/log servers
/usr 2048M or 4096Mb ( /usr/local can be /opt/local too ifneeded )
<swap> 2x ram
/opt rest of the disks ( /home is moved to /opt/home )
and i backup only /etc and /opt/home if needed
than all those partitions are stripped with its other drive
and/or mirrored.... for "mirroring"...
- whether you use raid0 or raid1 would depend on what is more
important to you....fast reads or possible fast recovery from disk crash
but NOT both...
have fun raiding...
alvin
On Fri, 19 Jan 2001, Knud [iso-8859-1] Sørensen wrote:
> Alvin Oga wrote:
> >
> > hi ya knud
> >
> > i dont think you wanna do that ???
> >
> > think you want something more like...
> >
> > /dev/mdx /dev/hda2 /dev/hdc2
> >
> > where they are all mkswap formats instead of normal ext2
> >
> > than it should work.....donno...never tried it...
>
> Are you suggesting that I run the swap space over the raid ?
>
> This was my primary intention too, to get high avability via raid1.
>
> But I read that the is some problem with that.
>
> That the raid need memory to swap, and that this memory then get swapped
> -> error.
>
> So, I decided to use the kernels stripe swapping.
>
>
>
> > but it does work for "stripped data"...
> >
> > and am assuming oyu have setup /etc/raidtab properly
> > too
> >
> > if you need to use swapp space that much...
> > add more memory......its only $45 for 64Mb or $65 for 128Mb ...
> > or even less on mailorder places ????
>
> There server i work on have 640Mb.
>
> But I have 2 identical disks.
> with raid1 on the first partition on each leaves me with 2 partitions
> if I only use one for swap, I still got on left.
>
> So, why not use it for stripe swapping and increase the speed of the
> swap space.
>
> Knud
>
> > amount of swap space constantly used...is a good guideline
> > for how much more memory you need to add to the system...
> >
> > have fun raiding...
> > alvin
> >
> > On Fri, 19 Jan 2001, Knud [iso-8859-1] Sørensen wrote:
> >
> > > Hi
> > >
> > > I trying to setup stripe swapping on two devices.
> > >
> > > The only thing i did was editing the fstab file to.
> > >
> > > /dev/hda2 none swap sw,pri=1 0 0
> > > /dev/hdc2 none swap sw,pri=1 0 0
> > >
> > > It don't work
> > >
> > > the partition type on hda2 and hdc2 is 82 (Linux swap)
> > >
> > > Do I need to do anything to the partion or adding a module to the
> > > kernel?
> > >
> > > any ideas ?
> > >
> > > knud
> > >
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