[asterisk-users] Asterisk RT on Disk On Module Performance and Durability

[Erick Perez]

I understand Jeremy and Kris point of view (BTW Kris, astlinux rocks!!)

However the main question was not aswered (or i didn't get it, did I ?)

If I use a Disk on Module that has 2million hours MTBF and a Read/Write
lifecycle of 2million times, then, How many days/weeks/months/years will
take to do 2million read/write cycles?
which leads to my second question.
How do I measure/count the read and writes a normal linux system running
asterisk does during a day, so I can extrapolate that in terms of time? Is
there an utility?

Example: if I setup system XYZ with asterisk, then load this magical
utility/procedure that counts how many writes the filesystem has done to /
or to /,/tmp,/var and after 24 hours the utility/procedure says: 10thousand
writes, then, I will do
10thousand writes a day multiplied by 200 days = 2 millions
Obviously this means I will not use a RAM disk and I want to write to the
module everytime

Then i will assume that the Disk on a Module will die after 200 days. Or am
I completely and horribly misunderstanding the "2million
Read/Write LifeCyle" advertised by Disk-on-Module companies?

Example:
http://www.pqi.com.tw/product2.asp?oid=140&cate1=143&PROID=34
‧MTBF:2,000,000 Hours
‧R/W Cycle:2,000,000 Times

I want to understand if that's what they mean.

I fully understand that such media will have a longer life cycle if i only
read from it and keep writes to a mimimum, for example: writing dialpan
changes.

The whole idea comes from doing a mini itx with no moving parts offering
voicemail stored in a disk-on-module and astlinux in a CF and a RAM Disk
large enough to do processing on RAM before saving to CF or to
disk-on-module when needed.

Thanks again for you comments,




On 10/6/06, Kristian Kielhofner <kris at krisk.org> wrote:
>
> Kristian Kielhofner wrote:
> >
> > Erick,
> >
> >     Or....  Just use AstLinux which kind of does what Jeremy described
> :)
> >
> > http://www.astlinux.org
> >
> >
> > P.S. - I am the creator of AstLinux
> >
> > --
> > Kristian Kielhofner
>
>        Sorry to reply to my own post, but there seems to have been some
> confusion in what I said here.  To completely clear it up, Astlinux only
> writes to flash in these circumstances:
>
> 1)  You update the configs.
>
> 2)  You update AstLinux.
>
> 3)  You are using voicemail and people leave voicemail. (most flash
> seems to last "long enough" given typical voicemail usage patterns)
>
> 4)  If you have the PERSISTLOG option enabled, I will save syslogs to
> flash (not RAM - the default).  Users are warned about this, and it is
> not the default.
>
> 5)  astdb is stored in flash, so depending on your needs, SIP
> registrations and/or dundi keys may get written here periodically.  I
> might make an option similar to PERSISTLOG to disable this.
>
>        Also, you have the option of using a hard drive or alternate flash
> device for ALL writes.  Boot from flash, run from HD.  Do whatever works
> best for you and your application.
>
> --
> Kristian Kielhofner
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-- 
------------------------------------------------------------
Erick Perez
Panama Sistemas
Integradores de Telefonia IP y Soluciones Para Centros de Datos
Panama, Republica de Panama
Cel Panama. +(507) 6694-4780
------------------------------------------------------------
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