> On Wed, 20 Jul 2011 09:13:34 +1200, Gregory Machin wrote: > > Hi. > > Been a long time since I last looked at a squid proxy. After add a > > proxy to the network , browsing seems to have slowed considerably. I > > have build a squid proxy , this is configured into the network on via > > our Sonicwall using the proxy feature. When I looked into the > > configuration I did a few optimizations based on what I found on a > > couple of websites. All though I opted not to tweak the OS more than > > increase the ulimit as I would not expect it to be required given the > > hardware. It is running out of a SSD drive. > > > > Two things in general to be aware of. > > * Careful with SSD. Squid is a mostly-write software, SSD work best > with mostly-read. So SSD lifetime and speed is reduced from the well > advertised specs. That said, they can still improve caching HIT speeds.
I think this must be made a FAQ entry. As someone who has worked with SSDs since 2004, I can very easily say that SSDs are good only for read-only operations still in 2011. Anything requiring writes should be taken off SSDs. I had lenghty discussions and benchmarks on these matters in StorageReview and Anandtech since years. Things seem to be working fine for couple of months. Then SSDs are crippled beyond repair no matter how many ATA secure erases are done. I had Intel SSD's that required a secure erase for every TB written just to be able to function properly. I had SandForce SSDs that worked well, however, their garbage collection routines were so overloaded that it was taking for me 20 seconds to send an IM message when something was written to the disk. All these were partitioned 10-20% less capacity to allow room for write amplification beyond manufacturer defaults. I keep my access.log and cache.log out of SSD (I don't cache). I really do not want to imagine what happens on a busy caching squid with an SSD. This should be a disaster waiting to happen, if it is not already happenning. Jenny
