SSD Cache

key900

Hello,

I'm looking to use SSD cache, Some Hardware seller procide me LSI MegaRAID 9265-8i if planing use SSD cache and some other provide normal 3ware 9750-4i

So i'm very Confused now i don't know who is right.

john

The 3ware 9750-4i is basically the 3ware version of the LSI 9260-4i. The 9265 has a dual core chip compared to the 9260's single core.

key900

Hello,

Then how i"d using SSD cache?

I need to know how is?

john

LSI's caching solution is called CacheCade.

Damian

You can also use a software solution, using any onboard SATA controllers your motherboard may have:

https://github.com/facebook/flashcache/

Alex_LiquidHost

@Damian said: You can also use a software solution, using any onboard SATA controllers your motherboard may have:

https://github.com/facebook/flashcache/

I am about to test flashcache on a local server. Need to get a SSD only .. And will post results.

rds100

I tried facebook's flashcache on a test machine and am not too impressed. It does help some benchmarks but i am not sure how much benefit there will be with real production load. I think there is certainly room for improvement, software wise in the facebook's flashcache module. Unfortunately i don't have the time nor am i brave enough to make my own changes in the caching algorithm and test them,

serverbear

@miTgiB is using SSD Caching pretty successfully on his newer nodes, he might not give away his secrets but here's the results:

dd if=/dev/zero of=sb-io-test bs=1M count=1k conv=fdatasync
1.96858 s, 545 MB/s

That's on the OVZ-256 in his Charlotte DC.

miTgiB

@serverbear said: That's on the OVZ-256 in his Charlotte DC.

I have no nodes with SSD caching in Charlotte, only in LA, e3la17 and e5la18, and here is a test I did to show off the cache in action http://www.lowendbox.com/blog/review-hostigation-256-mb-openvz-monthly/#comment-77074

HalfEatenPie

so... @miTgiB is secretly a super secret computer hacker using a GUI interface in Visual Basics?

serverbear

@miTgiB said: I have no nodes with SSD caching in Charlotte

Hrm, that's pretty solid IO to not be using SSD's. Black magic? :P

miTgiB

@serverbear said: Black magic?

The e5clt19 node was my test system when I was thinking of changing from E3's to E5's and totally over spent on it, so it is just a real beast.

Nick_A

@key12 said: I'm looking to use SSD cache, Some Hardware seller procide me LSI MegaRAID 9265-8i if planing use SSD cache and some other provide normal 3ware 9750-4i

How many drives total?

rgenzon

Woah. Seen the comment from LEB that @miTgiB pointed out. Real beast 900 mb/s. Awesome result!

Alex_LiquidHost

Oh my god, this is awesome result.

What SSD card did you use and on what configuration of drives? And was this software solution like the one posted above (facebook flashcache, etc.)? @miTgiB

rds100

I don't want to rain on Tim's parade so i will not tell you what the 900MB/s result means :)

Alex_LiquidHost

@rds100 said: I don't want to rain on Tim's parade so i will not tell you what the 900MB/s result means :)

Go ahead .. ;d

I am not hoping in achieving 900MB/s, however if I can increase the IO from 150MB/s to 200MB/s, it is still great.

rds100

There is no (SATA) ssd that can read at 900MB/s. This read is probably coming from RAM (he did not do echo 1 > /proc/sys/vm/drop_caches between the tests)

miTgiB

@rds100 said: (he did not do echo 1 > /proc/sys/vm/drop_caches between the tests)

Damit, I got all excited once before with my first 6g raid card and didn't test larger than it's cache either. Finding good overall benchmarks is like snipe hunting, but tossing a WP site on a node that is trashing others without the cache and seeing it breeze along is test enough for me.