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These are old (320-520) SSDs we are using Intel 3500 & 3700 DC series and haven't had any issues. with few power outages in past few years. 840Pro is a consume

These are old (320-520) SSDs we are using Intel 3500 & 3700 DC series and haven't had any issues. with few power outages in past few years. 840Pro is a consumer grade drive and has reduced guaranteed max write capacity and larger variance in quality from unit to unit. Instead you should use server type disks instead: http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/why/forDataCenter.html http://www.samsung.com/global/business/semiconductor/minisit... We use these in our analytics servers, they have stood up to test of time many times, and without any issues. SSD tech evolves so fast that 3 years since release of model lineup seems like forever, especially in an intensive write prone environment(for example writing slows reading but by how much? DC level drives are way ahead in this and very consistent as per what we found out in our tryouts).

kustodian 11y ago
Yeah I know that these are old drives, we've done this testing about year and a half ago and when we started renting servers more than 5 years ago, we didn't think about which SSDs are in there. At that time we didn't have an option to choose, nor time to think about the implications of different SSD models, we used what we got. Later on when we grew and started having problems, we started investigating what models we should use. The main reason for writing this article is for people to be aware that they should test their drives and how to do it.
- acqq 11y ago
  What's the decision behind not testing Samsung with "On On" cache and barriers? Is it so much slower that it's not worth testing? Shouldn't barriers allow the cache on the disk to "know better" how to organize writes and still be faster than without the cache turned on? The "disk cache" is a disk hardware option (how it uses its own RAM), if I understood, and the barriers are just an option of the FS behavior (software). I'd expect that the performance penalty to the former is much higher than to the later?
  - kustodian 11y ago
    The reason is the performance penalty for barriers On + disk cache On was much higher than for barriers Off + Disk Cache off, at least that is how it looked like on our testing system. Of course that could be do to the fact that we are using a RAID controller which has a 1GB of cache. If you are not using RAID, "On On" would be a valid test.

kustodian 11y ago

Yeah I know that these are old drives, we've done this testing about year and a half ago and when we started renting servers more than 5 years ago, we didn't think about which SSDs are in there. At that time we didn't have an option to choose, nor time to think about the implications of different SSD models, we used what we got. Later on when we grew and started having problems, we started investigating what models we should use. The main reason for writing this article is for people to be aware that they should test their drives and how to do it.

acqq 11y ago
What's the decision behind not testing Samsung with "On On" cache and barriers? Is it so much slower that it's not worth testing? Shouldn't barriers allow the cache on the disk to "know better" how to organize writes and still be faster than without the cache turned on? The "disk cache" is a disk hardware option (how it uses its own RAM), if I understood, and the barriers are just an option of the FS behavior (software). I'd expect that the performance penalty to the former is much higher than to the later?
- kustodian 11y ago
  The reason is the performance penalty for barriers On + disk cache On was much higher than for barriers Off + Disk Cache off, at least that is how it looked like on our testing system. Of course that could be do to the fact that we are using a RAID controller which has a 1GB of cache. If you are not using RAID, "On On" would be a valid test.