From: Patrick Ben Koetter on
* Stan Hoeppner <stan(a)hardwarefreak.com>:
> Wietse Venema put forth on 7/21/2010 2:22 PM:
> > Ram:
> >> One server of ours just accepts the mails from clients and then relays
> >> the mails to other servers.
> >> Since there is almost no mail queued on the server , I think it is will
> >> be good to mount /var/spool/postfix on a tmpfs partition.
> >
> > You will lose all mail in the queue when the system crashes.
> > I agree with Victor that this is a really bad idea.
>
> +3
>
> If you truly have a _need_ for a super fast Postfix queue, I suggest using a
> good quality wear leveling SSD. You'll get random I/O performance many times
> greater than a 15k rpm disk, but with data persistence, unlike when using a
> ramdisk queue. There are many fast good quality SSDs available in various
> capacities for between $100-200 USD, in standard 2.5" and 3.5" hard disk
> mounting form factors.

You can get about 150 msg/sec a 100k on a single Postfix instance if you use
a set of 10k rpm discs in a RAID 0 and server hardware.

p(a)rick


--
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saslfinger (debugging SMTP AUTH):
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From: Stan Hoeppner on
Patrick Ben Koetter put forth on 7/22/2010 2:11 AM:
> * Stan Hoeppner <stan(a)hardwarefreak.com>:
>> Wietse Venema put forth on 7/21/2010 2:22 PM:
>>> Ram:
>>>> One server of ours just accepts the mails from clients and then relays
>>>> the mails to other servers.
>>>> Since there is almost no mail queued on the server , I think it is will
>>>> be good to mount /var/spool/postfix on a tmpfs partition.
>>>
>>> You will lose all mail in the queue when the system crashes.
>>> I agree with Victor that this is a really bad idea.
>>
>> +3
>>
>> If you truly have a _need_ for a super fast Postfix queue, I suggest using a
>> good quality wear leveling SSD. You'll get random I/O performance many times
>> greater than a 15k rpm disk, but with data persistence, unlike when using a
>> ramdisk queue. There are many fast good quality SSDs available in various
>> capacities for between $100-200 USD, in standard 2.5" and 3.5" hard disk
>> mounting form factors.
>
> You can get about 150 msg/sec a 100k on a single Postfix instance if you use
> a set of 10k rpm discs in a RAID 0 and server hardware.

If my math is correct, I believe Ram's relay server has a queue load of less
than 15 msg/sec on average, which is easily handled by a single SATA disk.

50,000/hr = 50,000/3600 = 13.88 msg/sec

Ram, why are you considering ramdisk or SSD for your Postfix queues given that
a regular disk would seem to handle your load rather easily? Or, is this more
of a philosophical issue of not wanting to write anything to disk that isn't
permanent?

--
Stan

From: Ram on
On Thu, 2010-07-22 at 04:50 -0500, Stan Hoeppner wrote:
> Patrick Ben Koetter put forth on 7/22/2010 2:11 AM:
> > * Stan Hoeppner <stan(a)hardwarefreak.com>:
> >> Wietse Venema put forth on 7/21/2010 2:22 PM:
> >>> Ram:
> >>>> One server of ours just accepts the mails from clients and then relays
> >>>> the mails to other servers.
> >>>> Since there is almost no mail queued on the server , I think it is will
> >>>> be good to mount /var/spool/postfix on a tmpfs partition.
> >>>
> >>> You will lose all mail in the queue when the system crashes.
> >>> I agree with Victor that this is a really bad idea.
> >>
> >> +3
> >>
> >> If you truly have a _need_ for a super fast Postfix queue, I suggest using a
> >> good quality wear leveling SSD. You'll get random I/O performance many times
> >> greater than a 15k rpm disk, but with data persistence, unlike when using a
> >> ramdisk queue. There are many fast good quality SSDs available in various
> >> capacities for between $100-200 USD, in standard 2.5" and 3.5" hard disk
> >> mounting form factors.
> >
> > You can get about 150 msg/sec a 100k on a single Postfix instance if you use
> > a set of 10k rpm discs in a RAID 0 and server hardware.
>
> If my math is correct, I believe Ram's relay server has a queue load of less
> than 15 msg/sec on average, which is easily handled by a single SATA disk.
>
> 50,000/hr = 50,000/3600 = 13.88 msg/sec
>
> Ram, why are you considering ramdisk or SSD for your Postfix queues given that
> a regular disk would seem to handle your load rather easily? Or, is this more
> of a philosophical issue of not wanting to write anything to disk that isn't
> permanent?
>

You are right.
If Postfix alone was running on this server will be able to handle
(50k-70k msgs/hr) with the given I/O. But there are other custom
functions running on this machine.
I was just considering ramdisk , because that was the laziest way I
could get rid of unnecessary "IOPS" to disk.

Anyway I think I will go by what all you folk say. No ramdisk for
postfix.


Thanks for the inputs.
Ram