8x 1TB 840 Evo? why not.

Out of curiosity what is the mean time write to failure on these 1tb drives? I mean that is a wicked setup and all, but say you were running an heavy exchange and SQL server install on some VM's. What kind of burn through would you expect on the TLC cells? Also just from a learning standpoint, if I wanted to setup something similar, assuming raw performance was not a concern would it make sense to setup maybe one ssd to a vm (or placed them strategically) to reduce the wear on the drives?

I wouldn't want to do heavy VM's or SQL as yeah that is write heavy. My usage is primarily read access and I do not do heavy writes. in 2 months I have done:

Code:
root@方向音痴: 01:31 PM :~# df -h /ssd
Filesystem            Size  Used Avail Use% Mounted on
/dev/sdd              5.5T  2.2T  3.3T  40% /ssd
root@方向音痴: 01:31 PM :~# uptime
 13:31:25 up 62 days, 13:15,  7 users,  load average: 9.88, 8.88, 9.15
root@方向音痴: 01:31 PM :~# iostat -m sdd
Linux 2.6.39.4-houkouonchi-web10g-ioat-vlan (houkouonchi)       08/14/2014

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
          11.52    1.60    4.56    7.75    0.00   74.57

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sdd              72.73         9.44         0.02   51015953     101307

So only 101GB written but 51 TB read.
 
Because he would lose 2 more disks. Raid 6: 1TB * (N-2) = 6TB, Raid 10: 1TB * (N / 2) = 4TB

What he says:

I would be very concerned about write amplification on RAID6...

I tried R6 on Areca ARC1882ix-24 with 10 512GB 840 Pros. Disks all had zero data written (fresh specimens) and after an initialize they had over 1.6TB written! That's BEFORE the array was even put to use. RAID10 would be far better for durability concerns, especially with TLC parts.

Sure with SSD's you wont notice the hit like with mechanical on read/write and rebuild times. But i would worry about using "consumer" SSD drives for anything production that makes money for a company.

I would at least hope there are backups or HA or FT running just incase.

Comparing the price vs 1.2T SAS drives is not the right way to go, the price is the same because the SAS drives are tested to run 24/7 under high load in a server environment, those SSD's are not.
 
Nice. Most we've done here is six 512gb 840 pros in raid 10. Not enough space for what we needed it for in the end though.
 
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