[ale] Anyone know if this is true?
Ron Frazier
atllinuxenthinfo at c3energy.com
Thu Oct 13 14:40:43 EDT 2011
Thanks. LOL
Ron
On 10/13/2011 1:14 PM, Rich Faulkner wrote:
> Noob to Hawk in one easy lesson. Jump in the pool...down the rabbit
> hole with you!
>
>
> On Thu, 2011-10-13 at 13:07 -0400, Ron Frazier wrote:
>> Ahh, very clever. Hook me in with my own idea. 8-) I would
>> consider it. I'd also have to consider if I can allocate the 20+
>> hours it would probably take to get ready. My findings are currently
>> very very preliminary. Also, I'm one of the more newbie Linux users
>> in the group. I'm not sure how qualified I am. What did you have in
>> mind?
>>
>> Ron
>>
>> On 10/13/2011 11:51 AM, Jim Kinney wrote:
>>> So can you consider a presentation of your findinds and perhaps some
>>> testing?
>>> :-)
>>>
>>> On Oct 13, 2011 10:52 AM, "Ron Frazier"
>>> <atllinuxenthinfo at c3energy.com
>>> <mailto:atllinuxenthinfo at c3energy.com>> wrote:
>>>
>>> Hi guys,
>>>
>>> This thread has prompted me to do a bit of research to try to
>>> see if I can find a consensus on the swap size issue. At the
>>> moment, it seems like ask 100 people and get 100 different
>>> opinions. I haven't uncovered enough data to tabulate and
>>> summarize it at this point. I'm pretty sure my linux machines
>>> have plenty of swap for applications. I have 8 GB of swap on
>>> two machines which have 8 GB of RAM. If I look at the system
>>> monitor program in Gnome, it looks like the swap is rarely ever
>>> touched. By the way, having 8 GB of RAM in a laptop is a nice,
>>> new, liberating experience for me. It's really nice to be able
>>> to open several dozen browser tabs and a dozen or more
>>> applications without the machine even breathing too hard. This
>>> is my first laptop capable of that. I also have 8 GB of swap on
>>> a machine with 4 GB of RAM, so it should be sitting pretty, so
>>> to speak. I haven't found anything that says extra swap is
>>> harmful. What I don't know, is whether the two 8 GB machines
>>> would be able to hibernate (suspend to disk) properly, if the
>>> swap is equal to the RAM. I may have to increase the swap on
>>> those to 10 GB - 12 GB. This is not an issue in Windows since
>>> it uses a separate hibernate file.
>>>
>>> In my research, I found this article (
>>> http://lukasz.szmit.eu/2009/11/compcache-swap-on-linux-desktop.html
>>> ). The article is a bit old, but this talks about a fascinating
>>> project called Compcache. Here's a quote from the page:
>>>
>>> ---> quote on <---
>>>
>>> Compcache is an open source project implementing an innovative
>>> approach to swap. This has been done before, but not for swap.
>>> Users of DOS and early Windows versions will remember
>>> DoubleSpace/DriveSpace, which was used to virtually expand
>>> available disk space, by storing files in a compressed form.
>>> Compcache does exactly that, but for swap, by creating a new
>>> block device in the system which interfaces with the special
>>> compressed memory region in RAM. On the plus side, Compcache can
>>> also be configured to use an alternative swap device when the
>>> RAM swap area is full.
>>>
>>> ---> quote off <---
>>>
>>> I think that is a really cool idea for low resource machines.
>>> While I don't know if I'll ever use it, since my modern machines
>>> have a decent amount of RAM, it could really benefit older,
>>> smaller machines. For example, I have an old IBM Thinkpad with
>>> 160 MB (yes MB) of RAM. I've pretty much retired the machine.
>>> It does run a GUI based version of Linux, just barely, but is
>>> painfully slow. The old 300 MHz processor doesn't help much
>>> either. I think I have an old version of Lubuntu on it.
>>> Anyway, this type of technology could give the machine more
>>> breathing room by compressing the memory, so it would be like
>>> having 256 MB of RAM. I also have an old Toshiba laptop which
>>> is topped out at 1 GB or RAM. Both Ubuntu 10.04 and Windows XP
>>> run pretty well. However, I could compress 512 MB of RAM and
>>> then effectively have 512 MB or normal RAM and 1 GB of swap.
>>>
>>> Here's the link for the Compcache project:
>>> http://code.google.com/p/compcache/
>>>
>>> Here's an interesting quote from their site: "With compcache at
>>> hypervisor level, we can compress /any/ part of /guest/ memory
>>> transparently."
>>>
>>> Now, while I'll admit I don't understand all the implications of
>>> that statement, it looks like you could essentially compress all
>>> the RAM if running a lightweight hypervisor and running your OS
>>> as a guest.
>>>
>>> The project website also points out that embedded systems could
>>> benefit from the technology, where you have to justify every
>>> chip you put into a device.
>>>
>>> Finally, here is an interesting quote from the original article:
>>>
>>> ---> quote on <---
>>>
>>> On my desktop, a Dell Precision S390 with 2GB DDR2 RAM and a
>>> Maxtor Diamond Max 9 80GB drive, I am getting the following
>>> hdparm results (average of three runs) for my disk swap, and my
>>> compcache swap:
>>>
>>> * Swap on disk: 58MB/s
>>> * Compcache swap: 557MB/s
>>>
>>> An order of magnitude better bandwidth at no expense? I like that.
>>>
>>> ---> quote off <---
>>>
>>> I like that idea too. I'd like to know what you guys think of
>>> this concept.
>>>
>>> Sincerely,
>>>
>>> Ron
>>>
>>> On 10/13/2011 8:58 AM, Rich Faulkner wrote:
>>>> For me depends upon the system as to swap size, but if I plan
>>>> on using hibernation features I have swap just over the size of
>>>> RAM as in 1-1/2 times as the general (old) rule that I've
>>>> followed...generally a couple of gigs for a desktop and I leave
>>>> it at that. Being as I'm only building desktops and laptops
>>>> lately I'm not speaking to servers. An interesting experiment
>>>> is to do test installs to various system configs and see what a
>>>> given distro will do for a default installation. I consider
>>>> this a benchmark from the developers on an "ideal"
>>>> configuration given the hardware provided. RinL
>>>>
>>>>
>>>> On Thu, 2011-10-13 at 08:45 -0400, Scott Castaline wrote:
>>>>> On 10/12/2011 09:40 PM, Tavarvess Ware wrote:
>>>>> >
>>>>> > Scott I read the ram x 2= swap in my Linux classes as well and have
>>>>> > generally followed that, but with memory soaring as it has lately i am
>>>>> > starting to rethink that. A system 48gigs of memory would be 96 in
>>>>> > swap..... I wonder if te old format has changed and I haven't heard yet.
>>>>> >
>>>>> I only go RAM x 2 = swap for the 1st 2 GB of RAM so 2GB RAM = 4GB swap.
>>>>> From there on it's RAM x 1 = swap so 4GB RAM = 6GB swap. So your 48 GB
>>>>> of RAM = 50GB swap, and yup that's one hell of a lot of swap space.
>>>>> >
>>>>> > On Oct 12, 2011 9:32 PM, "Scott Castaline"<skotchman at gmail.com <mailto:skotchman at gmail.com>
>>>>> > <mailto:skotchman at gmail.com>> wrote:
>>>>> >
>>>>> > On 10/12/2011 04:14 PM, planas wrote:
>>>>> > > On Wed, 2011-10-12 at 15:13 -0400, Geoffrey Myers wrote:
>>>>> > >> 'Just so you all know, when determining how much space to assign to
>>>>> > >> swap: Swap isn't just used for paging or virtual memory
>>>>> > management; swap
>>>>> > >> is also used by power management for suspend-to-disk
>>>>> > (hibernation). '
>>>>> > >>
>>>>> > >> I seriously don't know, so I'm asking.
>>>>> > >>
>>>>> > >
>>>>> > > I have seen that a good swap size is ~1.5x the RAM.
>>>>> > > --
>>>>> > > Jay Lozier
>>>>> > > jslozier at gmail.com <mailto:jslozier at gmail.com> <mailto:jslozier at gmail.com>
>>>>> > >
>>>>> > >
>>>>> > >
>>>>> > I remember from somewhere that upto 2GB use 2.0x RAM above 2GB of
>>>>> > RAM go
>>>>> > with 1:1 ratio so 4Gb RAM = 6GB swap. I don't remember why 2x on the
>>>>> > first 2GB and this goes back to when 4GB was a lot on pre-configured
>>>>> > retail boxes. So like Geoffrey I can't see having 18GB of swap for a
>>>>> > 16GB machine.
>>>>> >
>>>>>
>>>
>>
>> --
>>
>> (PS - If you email me and don't get a quick response, you might want to
>> call on the phone. I get about 300 emails per day from alternate energy
>> mailing lists and such. I don't always see new messages very quickly.)
>>
>> Ron Frazier
>>
>> 770-205-9422 (O) Leave a message.
>> linuxdude AT c3energy.com
>> _______________________________________________
>> Ale mailing list
>> Ale at ale.org <mailto:Ale at ale.org>
>> http://mail.ale.org/mailman/listinfo/ale
>> See JOBS, ANNOUNCE and SCHOOLS lists at
>> http://mail.ale.org/mailman/listinfo
>>
>
>
> _______________________________________________
> Ale mailing list
> Ale at ale.org
> http://mail.ale.org/mailman/listinfo/ale
> See JOBS, ANNOUNCE and SCHOOLS lists at
> http://mail.ale.org/mailman/listinfo
>
--
(PS - If you email me and don't get a quick response, you might want to
call on the phone. I get about 300 emails per day from alternate energy
mailing lists and such. I don't always see new messages very quickly.)
Ron Frazier
770-205-9422 (O) Leave a message.
linuxdude AT c3energy.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.ale.org/pipermail/ale/attachments/20111013/dcbc13f4/attachment.html
More information about the Ale
mailing list