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Old 02-02-2012, 05:37 PM
William Warren
 
Default SSD Drives

On 2/2/2012 1:19 PM, Matt wrote:
> Has anyone installed a high I/O application such as an email server on
> SSD drives? Was thinking about doing two SSD's in RAID1. It would
> solve my I/O latency issues but I have heard that SSD's wear out
> quickly in high I/O situations? Something like each memory location
> only has X many writes before its done. Just wandering if anyone has
> tested it and if newer SSD's are better about this?
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
it all depends on how much writing you do AND how much spare space the
drives have. The more spare flash the drives have the longer they'll
live due to being able to spread the writing wear over a larger area.
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Old 02-02-2012, 06:05 PM
Mike
 
Default SSD Drives

On Thu, 2 Feb 2012, William Warren wrote:

> On 2/2/2012 1:19 PM, Matt wrote:
>> Has anyone installed a high I/O application such as an email server on
>> SSD drives? Was thinking about doing two SSD's in RAID1. It would
>> solve my I/O latency issues but I have heard that SSD's wear out
>> quickly in high I/O situations? Something like each memory location
>> only has X many writes before its done. Just wandering if anyone has
>> tested it and if newer SSD's are better about this?
>>
> it all depends on how much writing you do AND how much spare space the
> drives have. The more spare flash the drives have the longer they'll
> live due to being able to spread the writing wear over a larger area.
>
How very timely, I'm just starting to investigate something similar
myself. I don't have much to contribute however this forum post:
http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm
seems as though it'll be interesting, if I can ever make it through 3500+
pages to get to the conclusion.

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Old 02-02-2012, 06:15 PM
Peter A
 
Default SSD Drives

On 02/02/12 14:05, Mike wrote:
> On Thu, 2 Feb 2012, William Warren wrote:
>
>> On 2/2/2012 1:19 PM, Matt wrote:
>>> Has anyone installed a high I/O application such as an email server on
>>> SSD drives? Was thinking about doing two SSD's in RAID1. It would
>>> solve my I/O latency issues but I have heard that SSD's wear out
>>> quickly in high I/O situations? Something like each memory location
>>> only has X many writes before its done. Just wandering if anyone has
>>> tested it and if newer SSD's are better about this?
>>>
>> it all depends on how much writing you do AND how much spare space the
>> drives have. The more spare flash the drives have the longer they'll
>> live due to being able to spread the writing wear over a larger area.
>>
> How very timely, I'm just starting to investigate something similar
> myself. I don't have much to contribute however this forum post:
> http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm
> seems as though it'll be interesting, if I can ever make it through 3500+
> pages to get to the conclusion.
>
If you're worried about io reliability, then buy a (way more expensive)
SLC drive, rather than the consumer level MLC... We have some SLC drives
here that from their manufacturer have been rated at 3 or more years of
100% write 24x7...

Peter.

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Old 02-02-2012, 09:01 PM
William Warren
 
Default SSD Drives

On 2/2/2012 2:15 PM, Peter A wrote:
> On 02/02/12 14:05, Mike wrote:
>> On Thu, 2 Feb 2012, William Warren wrote:
>>
>>> On 2/2/2012 1:19 PM, Matt wrote:
>>>> Has anyone installed a high I/O application such as an email server on
>>>> SSD drives? Was thinking about doing two SSD's in RAID1. It would
>>>> solve my I/O latency issues but I have heard that SSD's wear out
>>>> quickly in high I/O situations? Something like each memory location
>>>> only has X many writes before its done. Just wandering if anyone has
>>>> tested it and if newer SSD's are better about this?
>>>>
>>> it all depends on how much writing you do AND how much spare space the
>>> drives have. The more spare flash the drives have the longer they'll
>>> live due to being able to spread the writing wear over a larger area.
>>>
>> How very timely, I'm just starting to investigate something similar
>> myself. I don't have much to contribute however this forum post:
>> http://www.xtremesystems.org/forums/showthread.php?271063-SSD-Write-Endurance-25nm-Vs-34nm
>> seems as though it'll be interesting, if I can ever make it through 3500+
>> pages to get to the conclusion.
>>
> If you're worried about io reliability, then buy a (way more expensive)
> SLC drive, rather than the consumer level MLC... We have some SLC drives
> here that from their manufacturer have been rated at 3 or more years of
> 100% write 24x7...
>
> Peter.
>
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
exactly hence why i said stay with OCZ or Intel..MLC drives are the
best. But also the smaller the process node the shorter the lifespan of
the flash. MLC drives will also over provision more spare flash area
most times.
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Old 02-02-2012, 09:19 PM
Peter A
 
Default SSD Drives

On 02/02/12 17:01, William Warren wrote:
> On 2/2/2012 2:15 PM, Peter A wrote:
>> If you're worried about io reliability, then buy a (way more expensive)
>> SLC drive, rather than the consumer level MLC... We have some SLC drives
>> here that from their manufacturer have been rated at 3 or more years of
>> 100% write 24x7...
>>
>> Peter.
>>
>> _______________________________________________
>> CentOS mailing list
>> CentOS@centos.org
>> http://lists.centos.org/mailman/listinfo/centos
> exactly hence why i said stay with OCZ or Intel..MLC drives are the
> best. But also the smaller the process node the shorter the lifespan of
> the flash. MLC drives will also over provision more spare flash area
> most times.
Aeh... that's exactly the opposite of what I said. MLC (multi level
cell) SSDs store more than one bit per cell. In current devices that's
mostly 2 bits per cell, but more is around the corner. On an SLC (single
level cell) there is only one bit per cell - true binary just like what
we have in RAM and others. SLC devices are superior in reliability
because it simply takes a lot more disturbing of a cell to make it lose
enough charge that a 1 gets interpreted as a 0. The devices are also
usually faster, especially on a re-write basis.
A Oracle 96GB flash card (SLC) physically has 128GB. Most consumer MLC
devices with 128GB are sold as 120GB visible... Again in favor of the
SLC. Only problem is that you pay for what you get. SLC devices are
significantly more expensive. Fusion I/O and all the other server ssd
vendors do the same - they give you a cheap MLC device with limited
performance and reliability and a high end, much more pricey SLC unit.

Peter.
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Old 02-03-2012, 03:20 PM
William Warren
 
Default SSD Drives

On 2/2/2012 5:19 PM, Peter A wrote:
> On 02/02/12 17:01, William Warren wrote:
>> On 2/2/2012 2:15 PM, Peter A wrote:
>>> If you're worried about io reliability, then buy a (way more expensive)
>>> SLC drive, rather than the consumer level MLC... We have some SLC drives
>>> here that from their manufacturer have been rated at 3 or more years of
>>> 100% write 24x7...
>>>
>>> Peter.
>>>
>>> _______________________________________________
>>> CentOS mailing list
>>> CentOS@centos.org
>>> http://lists.centos.org/mailman/listinfo/centos
>> exactly hence why i said stay with OCZ or Intel..MLC drives are the
>> best. But also the smaller the process node the shorter the lifespan of
>> the flash. MLC drives will also over provision more spare flash area
>> most times.
> Aeh... that's exactly the opposite of what I said. MLC (multi level
> cell) SSDs store more than one bit per cell. In current devices that's
> mostly 2 bits per cell, but more is around the corner. On an SLC (single
> level cell) there is only one bit per cell - true binary just like what
> we have in RAM and others. SLC devices are superior in reliability
> because it simply takes a lot more disturbing of a cell to make it lose
> enough charge that a 1 gets interpreted as a 0. The devices are also
> usually faster, especially on a re-write basis.
> A Oracle 96GB flash card (SLC) physically has 128GB. Most consumer MLC
> devices with 128GB are sold as 120GB visible... Again in favor of the
> SLC. Only problem is that you pay for what you get. SLC devices are
> significantly more expensive. Fusion I/O and all the other server ssd
> vendors do the same - they give you a cheap MLC device with limited
> performance and reliability and a high end, much more pricey SLC unit.
>
> Peter.
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos
i mistyped meant to type slc...
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Old 02-07-2012, 11:05 AM
Michael Simpson
 
Default SSD Drives

On 2 February 2012 18:19, Matt <matt.mailinglists@gmail.com> wrote:
> Has anyone installed a high I/O application such as an email server on
> SSD drives? *Was thinking about doing two SSD's in RAID1. *It would
> solve my I/O latency issues but I have heard that SSD's wear out
> quickly in high I/O situations? *Something like each memory location
> only has X many writes before its done. *Just wandering if anyone has
> tested it and if newer SSD's are better about this?

Sun were recommending using SSDs for the ZIL in really big ZFS install
*years ago* so go for it.

As long as you are using TRIM then you avoid the slowdown that happens
once the ssd is full

http://docs.redhat.com/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Storage_Administration_Guide/newmds-ssdtuning.html

mike
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Old 02-07-2012, 07:08 PM
Nataraj
 
Default SSD Drives

On 02/02/2012 10:19 AM, Matt wrote:
> Has anyone installed a high I/O application such as an email server on
> SSD drives? Was thinking about doing two SSD's in RAID1. It would
> solve my I/O latency issues but I have heard that SSD's wear out
> quickly in high I/O situations? Something like each memory location
> only has X many writes before its done. Just wandering if anyone has
> tested it and if newer SSD's are better about this?
> _______________________________________________
> CentOS mailing list
> CentOS@centos.org
> http://lists.centos.org/mailman/listinfo/centos

Is this the best way to go? Much of the recent mail software, postfix,
dovecot etc has features which make it easier to set up redundant
mailservers and distribute the load across them. This will scale better
if your needs grow down the road. SSD's tend to be rather costly,
especially if your storage needs are high. I guess the main advantage
to a single server with SSD is lower power consumption.

What about RAID10?

Nataraj

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Old 05-24-2012, 12:38 AM
Gerry Reno
 
Default SSD drives

What does Fedora do currently, if anything, to optimize for solid-state drives (SSD).

Things like swap and logging can generate a huge number of writes. So I suppose those should maybe be placed on a
rotating drive if one is available but if not does Fedora do anything to reduce the amount of writes? Or is everything
related to SSD the responsibility of the user?






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Old 05-24-2012, 07:37 AM
Roberto Ragusa
 
Default SSD drives

On 05/24/2012 02:38 AM, Gerry Reno wrote:
> What does Fedora do currently, if anything, to optimize for solid-state drives (SSD).
>
> Things like swap and logging can generate a huge number of writes. So I suppose those should maybe be placed on a
> rotating drive if one is available but if not does Fedora do anything to reduce the amount of writes? Or is everything
> related to SSD the responsibility of the user?

I think Fedora aligns partitions to 1MiB boundaries and disables atime (with relatime),
both things are good for SSD drives.

Using tmpfs for /tmp is also ok.

I've been using SSD drives for a couple of years, and in my opinion
concerns about logs and swap are exaggerated.

And having swap on SSD is a GREAT thing if you use hibernation. :-)


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