SSD in production servers? or trustworthy place for storage?

[ViviTheMage]

I was thinking of offering SSD drives in my new VPS lineup....I want to be one of the first companies to actually offer it.

Anyone using SSD's in a RAID? 5/10?

What is the life expectancy of SSD's? Are SSD's not trustworthy just yet? Are the random reads/writes still slow since it has to do that block wipe/cache/wipe business?

Should I get the new Intel SSD drives? or has OCZ finally caught up?

 

[jkresh]

if you haven't read this already I would suggest taking a look at http://www.anandtech.com/IT/showdoc.aspx?i=3532 , I think it answers some of your questions. Also definitely appears that intel is still the best in the mainstream category (for server use anyway), there are significantly faster (and more expensive) ones that are slc based and designed for enterprise use.

seems like the biggest issue with good ssd's in raid now is that raid cards are too slow, so either go with raid 0 or software raid 5.

Because there are no moving parts (and therefore significantly lower chance of failure) raid 0 is possibly a viable option with ssd's where it would be crazy in a server environment with sas/sata platter based drives.

 

[ViviTheMage]

I will read through that link, thanks! Before I do, any model preferences right now that are worth jumping into? What is the difference in speed/IO with RAID0, compared to a single drive?

 

[deimos3428]

Originally posted by: ViviTheMage
I was thinking of offering SSD drives in my new VPS lineup....I want to be one of the first companies to actually offer it.

This isn't quite what you're talking about, but SUN is using SSDs in their Sun Storage 7410 as "cache accelerators". So I'd say the technology in general is production-ready.

http://www.sun.com/storage/dis...storage/7410/specs.xml

 

[ViviTheMage]

I do not need anything THAT high grade. I am talking consumer level..OCZ, Intel, etc type of SSD's.

 

[jkresh]

ViviTheMage, if you are talking consumer grade (mlc vs slc), then its really the intel g2 drives, maybe ocz vertex (but there random is a bit below the intel, though sequential writes are faster). Considering the price/gb right now unless you absolutely need the best sequential writes and don't care about random then you should go with intel (and for the best possible sequential writes its still cheaper to go with sas and a bunch of 15k drives, ssd's really take off when it comes to random).

 

[alcoholbob]

There's some concern about heavy write random IOPS on SSDs. As you know the cache-less JMicron designs result in 500ms write latency. When you run out of cache in any hard disk your latency will increase substantially. Flash memory's steady-state write latency is higher than mechanical hard drives.

There was a poster here named Mikeblas that claimed his company was testing X25-E arrays and with sustained write IOPs the drives started stuttering when the load surpassed the available cache. SAS drives slowed down considerably but not with 1/2 dropouts.

 

[ViviTheMage]

thanks Astrallite, I think I will still hold off then, wait for prices to come down, and a few things to get 'fixed' to use them heavily.

And jkresh, I will probably stick with 15K SCSI drives then, thanks

 

[taltamir]

the intel drives are superior to anything mechanical in every possible way, especially random writes.
As for reliability... spindle drives are much more likely to fail. An SSD has enough writes to last a VERY long time, and when it runs out of writes, it SHOULD becomes read only memory (like a CDROM) not fail.

I wouldn't use an SSD From someone other than intel in a fileserver.

 

[alcoholbob]

Intel has increased it's cache from 32MB to 64MB with the G2 which was definitely a very prudent thing to do. Given the long erase cycles of SSDs, more cache means more leeway when it comes to heavy server use. Samsung definitely had the right idea when they decided to put 128MB of cache on their drives. If you can burn through that much cache you really need to consider some sort of (expensive) cutting edge storage technology.

 

[Emulex]

you need a battery on the drive to handle its write back cache. otherwise power pull could be fatal on a server

 

[taltamir]

Originally posted by: Astrallite
Intel has increased it's cache from 32MB to 64MB with the G2 which was definitely a very prudent thing to do. Given the long erase cycles of SSDs, more cache means more leeway when it comes to heavy server use. Samsung definitely had the right idea when they decided to put 128MB of cache on their drives. If you can burn through that much cache you really need to consider some sort of (expensive) cutting edge storage technology.

the intel does not have cache, it has RAM used by its PROCESSOR to run wear leveling and garbage collection algorithms. Not a SINGLE BIT of your data is cached.

Originally posted by: Emulex
you need a battery on the drive to handle its write back cache. otherwise power pull could be fatal on a server

AFAIK drives use capacitors instead of batteries for that, but it is still risky. The intel avoids the problem but not using a cache, at all.

 

[betaflame]

A power pull will not be fatal to the raid, simply corrupting the file in transit. Which can generally be redownloaded/transferred. Also decent UPSes that will give you 15-20min runtime are $100 now, so that's a good investment anyways.

A caveat is what controller you are using, if you lose all your data on a power loss, that's a shitty controller. Even the integrated ICH-R and software RAIDs won't nuke the entire raid. NTFS and most of the linux FSes have multiple File Tables anyway.

 

[Idontcare]

Originally posted by: taltamir

Originally posted by: Astrallite
Intel has increased it's cache from 32MB to 64MB with the G2 which was definitely a very prudent thing to do. Given the long erase cycles of SSDs, more cache means more leeway when it comes to heavy server use. Samsung definitely had the right idea when they decided to put 128MB of cache on their drives. If you can burn through that much cache you really need to consider some sort of (expensive) cutting edge storage technology.

the intel does not have cache, it has RAM used by its PROCESSOR to run wear leveling and garbage collection algorithms. Not a SINGLE BIT of your data is cached.

Originally posted by: Emulex
you need a battery on the drive to handle its write back cache. otherwise power pull could be fatal on a server

AFAIK drives use capacitors instead of batteries for that, but it is still risky. The intel avoids the problem but not using a cache, at all.

All of which is irrelevant in the event of power-loss.

Whether your unwritten data at time of power-loss was temporarily residing in the cache of your hard-drive waiting to be written to non-volatile media or it was residing in the cache of your system's ram waiting to be written to non-volatile media, the data are lost should the system experience a power-outage.

 

[taltamir]

Originally posted by: Idontcare

Originally posted by: taltamir

Originally posted by: Astrallite
Intel has increased it's cache from 32MB to 64MB with the G2 which was definitely a very prudent thing to do. Given the long erase cycles of SSDs, more cache means more leeway when it comes to heavy server use. Samsung definitely had the right idea when they decided to put 128MB of cache on their drives. If you can burn through that much cache you really need to consider some sort of (expensive) cutting edge storage technology.

the intel does not have cache, it has RAM used by its PROCESSOR to run wear leveling and garbage collection algorithms. Not a SINGLE BIT of your data is cached.

Originally posted by: Emulex
you need a battery on the drive to handle its write back cache. otherwise power pull could be fatal on a server

AFAIK drives use capacitors instead of batteries for that, but it is still risky. The intel avoids the problem but not using a cache, at all.

All of which is irrelevant in the event of power-loss.

Whether your unwritten data at time of power-loss was temporarily residing in the cache of your hard-drive waiting to be written to non-volatile media or it was residing in the cache of your system's ram waiting to be written to non-volatile media, the data are lost should the system experience a power-outage.

Both of those scenarios are NOT relevant to the intel, reread what i said... The 64MB on the intel is RAM for the built in processor... I was not saying it uses a software based cache in your regular ram... basically the intel is a cache free drive, meaning that the drive only says "I wrote it" when it actually wrote it...

And other drives are not guaranteed to lose data at a power loss, because their capacitor allows them to keep on writing data for a few more seconds.

 

[Emulex]

take a look at the gen 2 x25-e they will have a battery. wonder why? no reason?

netapp tried to do the tier-0 cache with ssd but gave up and went to traditional.

really the problem is how are you going to connect to your san to move that kind of i/o? even FCOE would be too weaksauce.

need some infiniband. the fusionio stuff uses pci express 2.0 4x per unit (it is raidable sorta) but having storage in pci express slots seems a little sketchy.

 

[Hacp]

Originally posted by: taltamir
the intel drives are superior to anything mechanical in every possible way, especially random writes.
As for reliability... spindle drives are much more likely to fail. An SSD has enough writes to last a VERY long time, and when it runs out of writes, it SHOULD becomes read only memory (like a CDROM) not fail.

I wouldn't use an SSD From someone other than intel in a fileserver.

Are you serious? Or just an idiot?

 

[RebateMonger]

Originally posted by: Hacp
Are you serious? Or just an idiot?

Hacp,

There is no justification for name-calling in a technical discussion. Please refrain from this.

RebateMonger
AnandTech Moderator