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A quick question relating to the write endurance different between the now affordable 'high end' consumer SSD's from the likes of Samsung and the very expensive 'enterprise' class SSD's?

Is this coming closer to a marketing game? Or is there a genuine reason to go for the more expensive offering from the likes of intel?

Other threads on here seem to lack hard evidence or are comparing the cheapest SSD's rather than at least the high end consumer grade such as the Samsung 850 Pro.

Tom

tomstephens89
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    http://serverfault.com/q/660715/126632 – Michael Hampton Aug 09 '15 at 16:40
  • Thanks but there wasn't much hard evidence in that thread and the comparison was with a 'cheap' SSD. When I say high end consumer I refer to something like the Samsung 850 Pro. – tomstephens89 Aug 09 '15 at 16:45
  • For example, based on this, even a consumer SSD such as the 850 Pro has excellent endurance: http://www.anandtech.com/show/8239/update-on-samsung-850-pro-endurance-vnand-die-size – tomstephens89 Aug 09 '15 at 16:51
  • Hahaha... "hard evidence" where computers -- especially SSDs -- are involved... ain't no such thing. – womble Aug 10 '15 at 00:31

2 Answers2

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SAS versus SATA is going to be more important in enterprise use cases. Any high-availbility system is going to want dual-ported (SAS) drives, and that's a major differentiator. This is in addition to the presence of a super-capacitor.

ewwhite
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  • Ahhh now I see the biggest difference then. To get the HA features that DP SAS offerers in Active/Active controllers set ups I need SAS SSD's... And at the moment the cost of SAS SSD's is INSANE! All the more reason to look more into large object storage pools such as ceph I suppose. – tomstephens89 Aug 09 '15 at 22:52
  • SAS SSDs don't have to be expensive. Dell and HP-branded devices can be bought on discount. Other manufacturers have diverse and workload-specific product lines. Look at the [Optimus line of SSDs](http://www.sandisk.com/enterprise/sas-ssd/) from SanDisk. – ewwhite Aug 09 '15 at 23:06
  • Thanks for the advice, however some quick research into SAS SSD's from the likes of HP and Dell shows that they are very expensive when compared to their SATA counterparts. That Sandisk Optimus range is also very expensive. It still leaves the question open, are they worth the extra cash when a high end consumer SATA SSD or intel S3500 DC series SSD is so much cheaper, performs extremely well and supposedly is very reliable? – tomstephens89 Aug 10 '15 at 08:33
  • I don't even consider consumer SATA disks anymore. However, when I did, I went through a lot of effort to find [inexpensive drives](http://eshop.macsales.com/shop/SSD/OWC/Mercury_6G/) that were compatible with my servers. But today, I need SAS or PCIe SSDs, so the cost difference doesn't matter because I have a business requirement. – ewwhite Aug 10 '15 at 11:07
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The big thing you should look for that makes a drive "Enterprise", regardless of how the drive is labeled and sold, is whether or not is has a supercapacitor to allow the drive to flush the write cache in case of sudden power loss.

Most RAID controllers make certain assumptions that are still based in the old "spinning metal" era of hard drives. These assumptions no longer hold and can really hurt performance in arrays with SSDs. In order to correct for this, SSD drives will often lie to RAID controllers that data in the cache has been flushed before it really happens. In addition, SSDs make heavy use of their cache in order to reduce write wear. This makes the whole array vulnerable to data loss in the case of sudden power loss, where data the RAID controller believed flushed to non-volatile storage was actually still in a cache. SSD drives with the extra supercapacitor protect against this.

There are some consumer-level drives that do have this feature, and some enterprise drives that do not.

Aside from this, enterprise SSDs typically have more raw space on the drive reserved for failed sectors, much like in the spinning metal days, but if you have a good and recent-make (not 1st or 2nd -gen) consumer SSD, you're probably still okay in this area.

Joel Coel
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