SSD drives in education

[SYNACK]

@zag You're right - they do have a limited write amount. No different to any other similar device including RAM though.

 

RAM does not have a measurable read/write failiure point as far as I have ever learnt, would be interested to see any data to the contrary though.

[synaesthesia]

I believe it's measurable, I just don't believe it's used because it's (nearly always) guaranteed to last beyond it's lifetime. Same with most such chips; I've only ever seen numbers quoted in military application.

[Arthur]

RAM does not have a measurable read/write failiure point as far as I have ever learnt, would be interested to see any data to the contrary though.

Although RAM doesn't appear to have a read/write failure point, the amount of errors seems to increase with age - as Google found out in a study they carried out three years ago. Obviously their servers get more of a pounding than the typical home user's laptop so for most people it doesn't matter. The laptop will probably break first!

 

DRAM Errors in the Wild: A Large-Scale Field Study

In this paper, we analyze measurements of memory errors in a large fleet of commodity servers over a period of 2.5 years. The collected data covers multiple vendors, DRAM capacities and technologies and comprises many millions of DIMM days.

 

The goal of this paper is to answer questions such as the following: How common are memory errors in practice? What are their statistical properties? How are they affected by external factors, such as temperature and utilization, and by chip-specific factors, such as chip density, memory technology and DIMM age?

 

[...]

 

Given that DRAM DIMMs are devices without any mechanical components, unlike for example hard drives, we see a surprisingly strong and early effect of age on error rates.

 

For all DIMM types we studied, aging in the form of increased correctable error (CE) rates sets in after only 10–18 months in the field.

 

On the other hand, the rate of incidence of uncorrectable errors continuously declines starting at an early age, most likely because DIMMs with UEs are replaced (survival of the fittest). (Source)

[Arthur]

Has anyone seen SanDisk's SSD prices? They are unbelievable!

 

Ultra - £33.32 for 60GB, £54.15 for 120GB

Extreme - £66.65 for 120GB, £133.32 for 240GB

Edited May 23, 2012 by Arthur

[localzuk]

Just read a couple of reviews, and they're Sandforce devices like the majority on the market (Crucial and Samsung are the odd ones out here), but the reason they can price so well is that they make their own flash memory! They've only just released them too - so potentially they could upset the apple cart and we could see significant dropping in price.

 

Their performance is up near the top of the grid too. Photographers swear by their high performance CF/SD cards so it'll be interesting to see just how good they are!

 

Oh, and they make a 480GB one too - Amazon have it at around £400. http://www.amazon.co.uk/dp/B006EKIQYM/ref=asc_df_B006EKIQYM7997455?smid=A3P5ROKL5A1OLE&tag=googlecouk06-21&linkCode=asn&creative=22206&creativeASIN=B006EKIQYM

Edited May 23, 2012 by localzuk

[sonofsanta]

Good lord that's incredo-cheap. Think I'd rather wait to see what reliability issues they have - some drives have been a bit flaky recently by all reports *cough* OCZ *cough* - but if they force the entrenched players to drop prices, it could be a big push towards making SSDs properly mainstream.

 

If all this can be done in the next month when I order the new PCs for work, as well, then I'm all smiles

[localzuk]

Good lord that's incredo-cheap. Think I'd rather wait to see what reliability issues they have - some drives have been a bit flaky recently by all reports *cough* OCZ *cough* - but if they force the entrenched players to drop prices, it could be a big push towards making SSDs properly mainstream.

 

If all this can be done in the next month when I order the new PCs for work, as well, then I'm all smiles

 

From everything I've read, the reliability of the OCZ Vertex 3 is much better than the old Vertex 2 (the numbers I've seen were about 4.6% failure rate for the 3, 9.8% or thereabouts for the 2), so the rates are getting better. Intel are in a league of their own though, with a 0.1% failure rate it seems! They focus on reliability over speed I think - which is what their main target market (business) is looking for.

 

Its going to be an interesting year all round for storage - as some of those hard disk manufacturers who lost facilities during the floods might be building flash fab sites instead of hard disk sites. And on top of that, memristers look to be set for a mainstream appearance soon.

[Tallwood_6]

I see intel are now using sandforce controllers not there own in some of there lower end ssd drives like the new 330 so I think the only real difference will be in the quality of the memory used and the firmware applied.

You have to be careful with the stats as a lot of the ones floating around for intel SSD's are for there previous generation drives which used SLC memory (more expensive and more reliable) not the MLC drives that are now mainstream.

OCZ and Intel drives generally attract a different customer base as well and so will see different kinds of data and handling by customers.

[zag]

I don't think Intel was using SLC memory in those tests. I have one of their original SLC SSDs and they were triple the price of the standard x25's at the time which were much more popular and just as reliable from my experience.

 

What makes Intel different is they used the older more reliable memory chips, while other manufacturers were installing the latest small die chips that were not as reliable.

 

And WOW those sandisk prices are amazing. I wouldn't touch them with a barge pole but nice to see competition entering the market. It will bring all the other prices down.

[synaesthesia]

Have put our drive orders on hold because prices are dropping like flies. 54 quid for the 120 Sandisk Ultra from ebuyer - it's "only" SATA2 but it's still a HUGE improvement on hard drives.

I see buying Intel's instead as an insurance policy - it's just gambling. Twice the money for what? Buy the Sandisks (or other brand of your choice), buy a few more just in case, claim on warranties if need be - and you still save a STUPID amount of money if buying in bulk.

[zag]

I see buying Intel's instead as an insurance policy - it's just gambling. Twice the money for what?

 

Reliability, plain and simple.

 

Paying more for Intel (still only 60 quid per drive) for virtually 100% guaranteed reliability is well worth it in my eyes.

Edited May 25, 2012 by zag

[Gibbo]

Have put our drive orders on hold because prices are dropping like flies. 54 quid for the 120 Sandisk Ultra from ebuyer

 

I've noticed the same. There was an offer on Amazon for a half price 120Gb SSD drive last week. The offer sold out within minutes and a few days later Ebay was swamped with them at inflated prices.

 

I hope those that bought to sell on Ebay have had their fingers burnt!

[Arthur]

Have put our drive orders on hold because prices are dropping like flies.

It's a good idea to wait. 240GB (and possibly 256GB) SSDs should be under £100 soon...

 

240GB OCZ Agility 3 - £124.99

 

^ I wonder which fly OCZ would be? Tsetse perhaps?

[sonofsanta]

Even Intel aren't immune to bugs :/ Anyone else had a repeat 8mb brick on 320 ssd AFTER firmware update.

 

So I'm definitely opting for Crucial m4s this summer - if even Intel have hit firmware problems, then I'm not going to worry about spending the extra on them. Samsung still have an excellent reputation, but I'm not convinced they've been around long enough at this point to truly tell (and they cost more than Crucial, importantly)

[mrbios]

Running 4 full IT suites out of 6 on SSDs now, best upgrade we've ever made to our machines, 3 of those suites are mini ITX, intel G840 or G620T cpus with 4GB ram, they're fantastic machines for less than £200 a pop (not inc monitor)

 

Trying out (read: experimenting) with consumer based SSDs in a SAN now, a local consultant has had a lot of success when they're in RAID6 (as generally due to block degradation they're likely to die quite close together in years to come) and as a tiered storage solution so they won't have a lot on them, just running SQL storage for example (which i might add is backed up daily and the backups checked regularly). Although fingers crossed the cost of enterprise SSDs will drop significantly along with the current SSD price drops, but £110 per 240GB SSD was not to be sniffed at on these

[pete]

This seems like a good a place as any to dump this:

 

Solid-state revolution: in-depth on how SSDs really work | Ars Technica

[pcstru]

Trying out (read: experimenting) with consumer based SSDs in a SAN now,

 

I'm very interested in anything you want to share on this. Please post your experiences etc!

[Arthur]

due to block degradation they're likely to die quite close together in years to come

Something else you can do to prolong the life of the NAND inside of the SSD is to increase the size of the spare area by decreasing the capacity of the drive (typically via MHDD). According to a presentation Intel gave at IDF 2009, endurance is increased by 3.5x if the capacity is reduced by 27%.

 

Assuming this applies equally to other makes, a 256GB Crucial M4 with its capacity reduced to 186.88GB should be capable of having at least 252 terabytes written to it (140GB per day over 5 years) instead of the usual 72TB (40GB/day).

 

 

http://i.imgur.com/Hd1xi.png http://i.imgur.com/0TsMr.png

[sonofsanta]

Something else you can do to prolong the life of the NAND inside of the SSD is to increase the size of the spare area by decreasing the capacity of the drive (typically via MHDD).

 

I normally just set the partition a bit smaller when running the Windows installation disc, that seems to do the trick. So long as there's spare room that the SSD knows about and Windows (etc.) doesn't, it gives the SSD controller the room to work with.

 

Assuming this applies equally to other makes, a 256GB Crucial M4 with its capacity reduced to 186.88GB should be capable of having at least 252 terabytes written to it (140GB per day over 5 years) instead of the usual 72TB (40GB/day).

What I am taking away from this is that I will never hit an average of 40Gb a day of writes on a small SSD on anything less than a server so it's probably fine.

[Arthur]

I normally just set the partition a bit smaller when running the Windows installation disc, that seems to do the trick.

That's fine too. I suppose the main advantage of limiting capacity via the SET_MAX_ADDRESS command is that it rules out human error in the future e.g. someone else sees the unused space in the disk management console and decides to increase the partition to fill the drive, or I re-install the OS and forget to make the partition a bit smaller.

 

What I am taking away from this is that I will never hit an average of 40GB a day of writes on a small SSD on anything less than a server so it's probably fine.

Yeah. For regular desktop users 40GB of writes per day is a lot. Even my three year old 160GB Intel X25-M 'G2' SSD which is used for VMs and updating WIM images with DISM has only had 15.29TB written to it over a period of 641 days (15,383 power-on hours). This works out to an average of 24 gigabytes of writes per day. Servers are a different matter however.

 

http://i.imgur.com/md9u7.png

[sonofsanta]

So... given how frustrating Intel's segmentation of the chipset market is, what difference is SATA3 compared to SATA2 likely to make on performance? The best figures I've seen are on the Samsung 830s which suggest 80k IOPs dropping to 47k going from 6Gbps to 3Gbps - but then compared to the jump from a 7.2k HDD at ~100 IOPS, is that seemingly significant difference actually a drop in the water? Obviously SATA3 would be lovely to have, but it's coming in at around a £30-£40 premium for motherboards with SATA3 and USB3, which I'd rather spend going to 8Gb of RAM from 4Gb.

 

The options I'm looking at are based around Crucial m4 128Gb drives, rather than the Samsungs, but I can't find an equivalent table to the above for the Crucials.

 

(on a related note: those Samsung SSDs are down to £77 for the 128gb and £143 for the 256gb, inc VAT, which is just astonishing value for the performance & reliability of those drives)

Edited June 14, 2012 by sonofsanta

[localzuk]

Its a very noticeable difference I found. I put an SSD in my laptop at home, and then in my desktop (same SSD) and the difference in speed was considerable. Eg. Startup time on laptop was 25 sec. On desktop it is 8 sec tops.

 

I'd be uneasy about buying out of date tech now - SATA3 has been out for several years now...

Edited June 14, 2012 by localzuk

[sonofsanta]

Its a very noticeable difference I found. I put an SSD in my laptop at home, and then in my desktop (same SSD) and the difference in speed was considerable. Eg. Startup time on laptop was 25 sec. On desktop it is 8 sec tops.

 

I'd be uneasy about buying out of date tech now - SATA3 has been out for several years now...

 

Believe me, I'm far from delighted about it - one quote has a motherboard with only a VGA output, it's another £9 to get the DVI port to connect natively to the new monitors, and DVI is a 13 year old standard - but a £32 premium for an H67 board over an H61 board just to get those SATA ports and USB3 is difficult to justify. I'm trying to get a few more computers out of the money than I planned to get (and therefore requested funds for), so it's a tough one. If it was a £10 premium then I'd go for it without question.

 

I suppose I could drop the 8Gb of RAM back to 4Gb, which would counteract the cost increase for SATA3... but with Windows 7's clever caching stuff, which would make the bigger difference in performance, bearing in mind that the RAM upgrade is cheaper than the mobo upgrade? (These PCs are going into the main IT teaching rooms, by the by, so Creative Suite and video editing and other fun stuff)

[SYNACK]

RAM is easier to fix later if it becomes an issue and the lack of it is more likely to be covered up by the SSDs, it will put more wear on them though. Motherboards are definatly a key component which you want to get right first time.

[sonofsanta]

RAM is easier to fix later if it becomes an issue and the lack of it is more likely to be covered up by the SSDs, it will put more wear on them though. Motherboards are definatly a key component which you want to get right first time.

 

...is a fair point.

 

You lot don't make this easy do you :/