Solid State Hard Drives

[Glenn Hocking]

Hi List

Had anyone had experience using Solid State Hard disks in mail servers?
I've heard that Solid State is very fast but not good for high read/write
functions such as mail servers as the drives wear out over time.

Be keen on any real world experience. Our mail servers have around 5000 mail
accounts.


Kind regards
Glenn Hocking
Woosaw Pty Ltd and Publish Media Pty Ltd
http://www.sitegeneral.com.au
office: [phone]
mobile: [phone]




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[steves-6]

Hi,

I'd be interested in hearing experiences on this too, but I would think
there would need to be a compelling reason for using them due to their
cost alone.  Are you experiencing I/O lag with normal hard drives?

Steve

On Thu, Oct 08, 2009 at 11:06:39AM +1100, Glenn Hocking wrote:

> Hi List
>
> Had anyone had experience using Solid State Hard disks in mail servers?
> I've heard that Solid State is very fast but not good for high read/write
> functions such as mail servers as the drives wear out over time.
>
> Be keen on any real world experience. Our mail servers have around 5000 mail
> accounts.
>
>
> Kind regards
> Glenn Hocking
> Woosaw Pty Ltd and Publish Media Pty Ltd
> http://www.sitegeneral.com.au
> office: [phone]
> mobile: [phone]
>
>
>
>
> --
> To UNSUBSCRIBE, email to debian-isp-REQUEST@...
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[Glenn Hocking]

Hi Steve

Running sendmail, qpopper, roundcube webmail, dspam, clamav-milter on a HP
DL360 G4 with 5000 accounts and it is struggling, time for an upgrade and
looking at all options. Solid State drives are not too expensive these days,
actually comparable to fast SAS drives with high end RAID controller.

Just wondering if Solid State Drives are at mature enough and reliable
enough for this type of application. Looking for real world experience
rather than theory......


Kind regards
Glenn Hocking
Woosaw Pty Ltd and Publish Media Pty Ltd
http://www.sitegeneral.com.au
office: [phone]
mobile: [phone]


-----Original Message-----
From: Steve Suehring [mailto:steves@...]
Sent: Thursday, 8 October 2009 12:03 PM
To: Glenn Hocking
Cc: debian-isp@...
Subject: Re: Solid State Hard Drives

Hi,

I'd be interested in hearing experiences on this too, but I would think
there would need to be a compelling reason for using them due to their
cost alone.  Are you experiencing I/O lag with normal hard drives?

Steve

On Thu, Oct 08, 2009 at 11:06:39AM +1100, Glenn Hocking wrote:
> Hi List
>
> Had anyone had experience using Solid State Hard disks in mail servers?
> I've heard that Solid State is very fast but not good for high read/write
> functions such as mail servers as the drives wear out over time.
>
> Be keen on any real world experience. Our mail servers have around 5000
mail

> accounts.
>
>
> Kind regards
> Glenn Hocking
> Woosaw Pty Ltd and Publish Media Pty Ltd
> http://www.sitegeneral.com.au
> office: [phone]
> mobile: [phone]
>
>
>
>
> --
> To UNSUBSCRIBE, email to debian-isp-REQUEST@...
> with a subject of "unsubscribe". Trouble? Contact

listmaster@...


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[Rodolfo Barbosa-2]

Hocking,

Which is your actual disk I/O technology. Is it SAS, SCSI or
SATA?

Regards
--
Rodolfo Barbosa
Lunar Consultoria
barbosa.rodolfo@...
CEL: [phone]

> -----Mensagem original-----
> De: Glenn Hocking [mailto:glenn@...]
> Enviada em: quarta-feira, 7 de outubro de 2009 22:53
> Para: 'Steve Suehring'
> Cc: debian-isp@...
> Assunto: RE: Solid State Hard Drives
>
> Hi Steve
>
> Running sendmail, qpopper, roundcube webmail, dspam,
> clamav-milter on a HP
> DL360 G4 with 5000 accounts and it is struggling, time
> for an upgrade and
> looking at all options. Solid State drives are not too
> expensive these days,
> actually comparable to fast SAS drives with high end
> RAID controller.
>
> Just wondering if Solid State Drives are at mature
> enough and reliable
> enough for this type of application. Looking for real
> world experience
> rather than theory......
>
>
> Kind regards
> Glenn Hocking
> Woosaw Pty Ltd and Publish Media Pty Ltd
> http://www.sitegeneral.com.au
> office: [phone]
> mobile: [phone]
>
>
> -----Original Message-----
> From: Steve Suehring [mailto:steves@...]
> Sent: Thursday, 8 October 2009 12:03 PM
> To: Glenn Hocking
> Cc: debian-isp@...
> Subject: Re: Solid State Hard Drives
>
> Hi,
>
> I'd be interested in hearing experiences on this too,
> but I would think
> there would need to be a compelling reason for using
> them due to their
> cost alone.  Are you experiencing I/O lag with normal
> hard drives?
>
> Steve
>
> On Thu, Oct 08, 2009 at 11:06:39AM +1100, Glenn Hocking
> wrote:
> > Hi List
> >
> > Had anyone had experience using Solid State Hard
> disks in mail servers?
> > I've heard that Solid State is very fast but not good
> for high read/write
> > functions such as mail servers as the drives wear out
> over time.
> >
> > Be keen on any real world experience. Our mail
> servers have around 5000
> mail
> > accounts.
> >
> >
> > Kind regards
> > Glenn Hocking
> > Woosaw Pty Ltd and Publish Media Pty Ltd
> > http://www.sitegeneral.com.au
> > office: [phone]
> > mobile: [phone]
> >
> >
> >
> >
> > --
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> REQUEST@...
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[Maarten Vink]

On 8 okt 2009, at 02:06, Glenn Hocking wrote:

> Hi List
>
> Had anyone had experience using Solid State Hard disks in mail  
> servers?
> I've heard that Solid State is very fast but not good for high read/
> write
> functions such as mail servers as the drives wear out over time.
>
> Be keen on any real world experience. Our mail servers have around  
> 5000 mail
> accounts.

Hi Glenn,

Some general advice: be sure to look for SLC-based flash drives, as  
opposed to MLC which is typically used in cheaper drives. SLC has way  
less problems with wear, and MLC suffers from relatively slow writes,  
which will be a problem when you're using them in a mailserver.

Regards,

Maarten


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[Glenn Hocking]

Hi Rodolfo

Currently the HP DL360 using SCSI Ultra 320 in RAID1 configuration.

If Solid State disks work as expected then the new mail server will be SATA2
using Solid State disks with either software or hardware RAID10.

Any thoughts on software vs hardware with Solid State disks? I'm thinking
software may be quicker and more reliable as there is no intermediate Cache
RAM as would exist on a hardware RAID controller.

If Solid State disks are not appropriate for a mail server then will use SAS
with hardware RAID10.


Kind regards
Glenn Hocking
Woosaw Pty Ltd and Publish Media Pty Ltd
http://www.sitegeneral.com.au
office: [phone]
mobile: [phone]


-----Original Message-----
From: Rodolfo Barbosa [mailto:barbosa.rodolfo@...]
Sent: Thursday, 8 October 2009 10:23 PM
To: debian-isp@...
Subject: RES: Solid State Hard Drives

Hocking,

Which is your actual disk I/O technology. Is it SAS, SCSI or
SATA?

Regards
--
Rodolfo Barbosa
Lunar Consultoria
barbosa.rodolfo@...
CEL: [phone]

> -----Mensagem original-----
> De: Glenn Hocking [mailto:glenn@...]
> Enviada em: quarta-feira, 7 de outubro de 2009 22:53
> Para: 'Steve Suehring'
> Cc: debian-isp@...
> Assunto: RE: Solid State Hard Drives
>
> Hi Steve
>
> Running sendmail, qpopper, roundcube webmail, dspam,
> clamav-milter on a HP
> DL360 G4 with 5000 accounts and it is struggling, time
> for an upgrade and
> looking at all options. Solid State drives are not too
> expensive these days,
> actually comparable to fast SAS drives with high end
> RAID controller.
>
> Just wondering if Solid State Drives are at mature
> enough and reliable
> enough for this type of application. Looking for real
> world experience
> rather than theory......
>
>
> Kind regards
> Glenn Hocking
> Woosaw Pty Ltd and Publish Media Pty Ltd
> http://www.sitegeneral.com.au
> office: [phone]
> mobile: [phone]
>
>
> -----Original Message-----
> From: Steve Suehring [mailto:steves@...]
> Sent: Thursday, 8 October 2009 12:03 PM
> To: Glenn Hocking
> Cc: debian-isp@...
> Subject: Re: Solid State Hard Drives
>
> Hi,
>
> I'd be interested in hearing experiences on this too,
> but I would think
> there would need to be a compelling reason for using
> them due to their
> cost alone.  Are you experiencing I/O lag with normal
> hard drives?
>
> Steve
>
> On Thu, Oct 08, 2009 at 11:06:39AM +1100, Glenn Hocking
> wrote:
> > Hi List
> >
> > Had anyone had experience using Solid State Hard
> disks in mail servers?
> > I've heard that Solid State is very fast but not good
> for high read/write
> > functions such as mail servers as the drives wear out
> over time.
> >
> > Be keen on any real world experience. Our mail
> servers have around 5000
> mail
> > accounts.
> >
> >
> > Kind regards
> > Glenn Hocking
> > Woosaw Pty Ltd and Publish Media Pty Ltd
> > http://www.sitegeneral.com.au
> > office: [phone]
> > mobile: [phone]
> >
> >
> >
> >
> > --
> > To UNSUBSCRIBE, email to debian-isp-
> REQUEST@...
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[Steve Kemp]

On Fri Oct 09, 2009 at 09:37:36 +1100, Glenn Hocking wrote:

> Any thoughts on software vs hardware with Solid State disks?

  You seem to be focusing upon very low-level details with a clear
 aim of "making things fast".

  But you've provided no details of what load you're seeing, what
 your bottlenecks are, and what the specific problem you're trying to
 solve is.

  All you've said is "5000 accounts" and "struggling".

  So, on that basis the answers you're going to receive are liable
 to be of the form "Yes using XX is faster than using YY" - when perhaps
 it would be more useful for you to learn if ZZ is fast enough already.

  I suggest you take a step back from this and profile your current
 system before planning the replacement.  Perhaps the disks are fine
 but the CPU is too weak.  Perhaps the disks and CPU are fine, but
 you're using too much memory, or are suffering from network links.

  [ObRant: Top posting, failing to trim irrelevant text from your
 replies is also annoying and makes people less inclined to reply.
 Or possibly just me.]

Steve
--
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http://www.debian-administration.org/


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[Michelle Konzack-2]

Am 2009-10-08 11:06:39, schrieb Glenn Hocking:
> Hi List
>
> Had anyone had experience using Solid State Hard disks in mail servers?
> I've heard that Solid State is very fast but not good for high read/write
> functions such as mail servers as the drives wear out over time.

I can not believe, that a 128 GByte SSD is FASTER then a 147  GByte  SAS
and the SAS cost me 230 Euro (my price as ISP), the SSD over 400...

Thanks, Greetings and nice Day/Evening
    Michelle Konzack
    Systemadministrator
    Tamay Dogan Network
    Debian GNU/Linux Consultant

--
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##################### Debian GNU/Linux Consultant #####################
<http://www.tamay-dogan.net/>                 Michelle Konzack
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[Andrew Miehs]

On 09/10/2009, at 1:06 AM, Michelle Konzack wrote:

> Am 2009-10-08 11:06:39, schrieb Glenn Hocking:
>> Had anyone had experience using Solid State Hard disks in mail  
>> servers?
>> I've heard that Solid State is very fast but not good for high read/
>> write
>> functions such as mail servers as the drives wear out over time.
>
> I can not believe, that a 128 GByte SSD is FASTER then a 147  GByte  
> SAS
> and the SAS cost me 230 Euro (my price as ISP), the SSD over 400...

And why not?

The change on the laptops I have seen is IMMENSE.

I would imagine SSDs are unbelievable on anything that requires random  
access.
If you are only streaming data off the disks, then I wouldn't bother -  
but
for something like a database or the spool folder of a busy mail  
server - I couldn't
imagine how anything could be quicker (other than a RAM disk).

I would be interested in any long term stress tests on the SLC disks.

Even if they only last 12 months - they are a LOT cheaper than trying  
to use a storage
system to get that sort of performance.

Regards

Andrew


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[Ward Vandewege]

On Fri, Oct 09, 2009 at 01:06:12AM +0200, Michelle Konzack wrote:
> Am 2009-10-08 11:06:39, schrieb Glenn Hocking:
> > Hi List
> >
> > Had anyone had experience using Solid State Hard disks in mail servers?
> > I've heard that Solid State is very fast but not good for high read/write
> > functions such as mail servers as the drives wear out over time.
>
> I can not believe, that a 128 GByte SSD is FASTER then a 147  GByte  SAS
> and the SAS cost me 230 Euro (my price as ISP), the SSD over 400...

It all depends on *which* SSD.

Someone said buy SLC. That's good advice. But, even within SLCs there
are big differences in performance. A lot depends on how smart the controller
embedded in the drive is. Even more depends on what it is optimized for. Most
SSDs are optimized for maximum sequential read and write. That's a shame,
because there are very few real world workloads that can benefit from that.
Intel does it differently. Their drives are optimized for random read/write
performance.

This article is more than 6 months old but explains this well, with real
performance numbers. On the upside, the drives have come down in price a lot
since then:

  http://www.anandtech.com/printarticle.aspx?i=3531

I would say buy Intel X25M, or, if your budget permits, X25E. Note that the
X25M is MLC but with random write performance that is way, way better than a
lot of SLCs out there.

There are other vendors that have high-performance offerings, but I think
you'll find them way more expensive and/or not really released yet. See for
instance:

  http://www.computerworld.com/s/article/9137909/Start_up_releases_uber_fast_efficient_enterprise_class_SSDs?taxonomyId=19

An X25E will *blow your spinning platter SAS drive out of the water*. I
suspect that even an X25M might, for most workloads.

Thanks,
Ward.

--
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Virtual hosting -(              operating systems." -- Linus               )-
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[Michelle Konzack-2]

Am 2009-10-09 01:23:00, schrieb Andrew Miehs:

> And why not?
>
> The change on the laptops I have seen is IMMENSE.
>
> I would imagine SSDs are unbelievable on anything that requires
> random access.
> If you are only streaming data off the disks, then I wouldn't bother
> - but
> for something like a database or the spool folder of a busy mail
> server - I couldn't
> imagine how anything could be quicker (other than a RAM disk).

He sayed, he has 5000 mail users...

I have here in Kehl/Germany on my server currently arround 700 users and
they have per day arround 140.000 mails.  the problem  is,  90%  of  the
mails come in 05:00-09:00 and 16:00-19:00 I have peeks of more  then  30
messages per second using a 1GE.

Oh yes, I am using courier-mta/imap and the random writes are very heavy
which mean, I would kill a SSD with the writes in less then 6 month...

> I would be interested in any long term stress tests on the SLC disks.

WHO want to risk the mails from customers?

> Even if they only last 12 months - they are a LOT cheaper than
> trying to use a storage
> system to get that sort of performance.

I am using a courir-imap-proxy (Sun Fire X4100), courier-mta  (Sun  Fire
X4100), two Sun Fire X4100 as spam/virus filter and currently  three SUN
Fire X4150 with 1 CPU and 16 GByte of memory as mail storage server.

The first two run from SATA-CF-Drives the filter has each three 76 GByte
drives and the storage servers (not only mail) use 147 GByte  (Raid-1  +
Hotfix for Data) and seperated small Raid for OS.

Thanks, Greetings and nice Day/Evening
    Michelle Konzack
    Systemadministrator
    Tamay Dogan Network
    Debian GNU/Linux Consultant

--
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##################### Debian GNU/Linux Consultant #####################
<http://www.tamay-dogan.net/>                 Michelle Konzack
<http://www.can4linux.org/>                   Apt. 917
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[Craig Sanders]

On Thu, Oct 08, 2009 at 12:53:15PM +1100, Glenn Hocking wrote:
> Running sendmail, qpopper, roundcube webmail, dspam, clamav-milter on
          ^^^^^^^^
> a HP DL360 G4 with 5000 accounts and it is struggling, time for an
> upgrade and looking at all options.

there's your problem. switch to postfix and watch your mail queue load
problems vanish instantly. i've done this numerous times over the years
on sendmail boxes that are struggling to keep up with the load - postfix
on the exact same hardware, with the exact same mail load copes without
even breaking a sweat.

also recommended: use some carefully selected RBLs such as
zen.spamhaus.org[1], as well as grey-listing. these will reject the
majority of spam before it gets to dspam/clamav and your mail queue,
greatly reducing both CPU and I/O load.

another recommendation: add more memory. as much as will fit into the
machine. memory is cheap[2] and is STILL the single most effective thing
you can do to improve the performance of any disk-I/O bound system like
a mail server.  With enough RAM to buffer the disks, many emails will
never touch the disk at all - queued, sent/delivered, or rejected and
then deleted entirely from RAM.


BTW, 5000 user accounts isn't a lot, certainly not for a DL360....but
it isn't the number of users that matter, it's the amount of mail the
server sends and receives...which has a lot more to do with spammers
(who will routinely spam thousands of non-existant addresses at your
domains) than it has to do with your users.

> Solid State drives are not too expensive these days, actually
> comparable to fast SAS drives with high end RAID controller.

and for the kind of usage pattern seen on mail servers, they'll slow
down to a crawl within weeks if not days.


rather than a flash SSD, you're probably better off putting the mail
queue drive on a RAM disk...not a software RAM disk (unless you're
a gambler), but a battery-backed hardware RAM disk like the ACARD
ANS-9010[3].  you probably wouldn't need more than 1 or 2 GB for
the mail queue.

these ACARD devices can take up to 64GB of DDR2-800 RAM (8 x 8GB
sticks), so depending on how much mail your 5000 users receive (and
store long-term) on your server it might even be possible to place the
mail spool (e.g. /var/mail and/or user Maildir directories) on the
ramdisk.


[1] http://www.spamhaus.org/zen/

[2] 1GB & 2GB memory sticks are dirt cheap.  4GB sticks are just
starting to become reasonably priced.  8GB sticks are still rare and
expensive.

[3] http://techreport.com/articles.x/16255

craig

--
craig sanders <cas@...>


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[Joerg Backschues-3]

Glenn Hocking wrote:

> Had anyone had experience using Solid State Hard disks in mail servers?

Move your mail queue to a RAM disk. That would be more efficient then
using solid state disks. Solid state disks are not reliable enough for a
huge of writing operations.

--
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[Joerg Backschues-3]

Craig Sanders write:

> rather than a flash SSD, you're probably better off putting the mail
> queue drive on a RAM disk...not a software RAM disk (unless you're
> a gambler), [...]

Software RAM disks are no problem for us. We are using a special version
of qmail that uses two queues:

The 1st queue only holds mails that can be delivered at the frist time.
This queue resides on the software RAM disk. All other mails will be
automatically moved to the 2nd queue that resides on a standard disk.
This is a compromise between safety and performance.

--
Greetings
Jörg Backschues


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[Maarten Vink]

>
> Oh yes, I am using courier-mta/imap and the random writes are very  
> heavy
> which mean, I would kill a SSD with the writes in less then 6 month...

That's a common misconception about SSDs; if you buy a recent drive,  
especially one meant for use in servers, there will be two mechanisms  
to prevent them from failing that soon:

- First, the drives include a wear-leveling algorithm, that prevents  
"data hotspots" where a single block of data is constantly being  
written to. Instead, writes are spread evenly over all flash cells.
- Second, most of these drives include extra capacity (sometimes quite  
a significant amount), that can be used to replace failed flash cells.

Regards,

Maarten


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[Henrique de Moraes Holschuh]

On Fri, 09 Oct 2009, Joerg Backschues wrote:

> Craig Sanders write:
> > rather than a flash SSD, you're probably better off putting the mail
> > queue drive on a RAM disk...not a software RAM disk (unless you're
> > a gambler), [...]
>
> Software RAM disks are no problem for us. We are using a special version
> of qmail that uses two queues:
>
> The 1st queue only holds mails that can be delivered at the frist time.
> This queue resides on the software RAM disk. All other mails will be
> automatically moved to the 2nd queue that resides on a standard disk.
> This is a compromise between safety and performance.

And a gross violation of every SMTP/ESMTP RFC that ever existed, unless
you DO hold the SMTP/ESMTP transaction open without returning a 2xx
reply to the DATA command until it is either delivered or moved to the
2nd queue...

--
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh


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[Matus UHLAR - fantomas]

> > Craig Sanders write:
> > > rather than a flash SSD, you're probably better off putting the mail
> > > queue drive on a RAM disk...not a software RAM disk (unless you're
> > > a gambler), [...]

> On Fri, 09 Oct 2009, Joerg Backschues wrote:
> > Software RAM disks are no problem for us. We are using a special version
> > of qmail that uses two queues:
> >
> > The 1st queue only holds mails that can be delivered at the frist time.
> > This queue resides on the software RAM disk. All other mails will be
> > automatically moved to the 2nd queue that resides on a standard disk.
> > This is a compromise between safety and performance.

On 10.10.09 19:15, Henrique de Moraes Holschuh wrote:
> And a gross violation of every SMTP/ESMTP RFC that ever existed, unless
> you DO hold the SMTP/ESMTP transaction open without returning a 2xx
> reply to the DATA command until it is either delivered or moved to the
> 2nd queue...

Yes - since you reply OK code to the DATA phase, you take responsibility for
the email and its delivery. Since then, the loss of e-mail is clearly in
your competence.

And note that the option to hold reply to DATA command can lead to multiple
deliveries and other delivery issues.
--
Matus UHLAR - fantomas, uhlar@... ; http://www.fantomas.sk/
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