On 13/05/2013 7:12 a.m., Alex Domoradov wrote:
SSDs have a huge but limited write operations.
and a hard disk doesn't have? :) You forgot to tell about IOPS
difference and random read/write speeds.
Have not tried them myself yet. But at least two of my customers have
used them on high-performance proxy situations and found that the SSD
lifetime is greatly reduced from manufacturer specs simply due to the
high write loading Squid sends to the disk. The speed does seems to be
higher than HDD, but again not quite as high as advertised - probably
due to the high proportion of slow(er) writes.
They are usable as a speed boost and indeed very useful for some
situations but you definitely need to look for quality or have the
budget available for replacement drives.
My advice on SSD:
* check that the brand you are using has a high (and fast) write I/O
capacity
* ensure you can afford replacement parts up to twice as often as the
manufacturer claims (approx. yearly disk turnover)
* if you are expecting many small objects use a rock cache type to
reduce the writes they need.
* if possible use a large memory cache, again to reduce disk loading.
* retain a mechanical HDD in the mix for the larger / less popular files.
HTH
Amos
