Re: Recommended/Not Recommended Hosts?

Jason DiCioccio wrote:
> On Fri, Dec 11, 2009 at 15:48, Sailesh Krishnamurthy <sailesh(at)gmail(dot)com> wrote:
>> Has anyone used EBS on EC2 ?
>> I/O is supposed to be much better on it
>
> My testing has shown it to still be pretty awful. Although Amazon
> does suggest doing software RAID on multiple EBS volumes. I haven't
> tried that yet.

The one thing I love about EC2 is that it's incredibly easy and
cheap to test such things. I just tried it for the cost of about $0.20.

(the script I used, and output from bonnie++ below)

Seek performance on the non-EBS default drive is poor -- but if I'm
reading the bonnie++ output right, the EBS volume otherwise wasn't
really faster - and perhaps even slower than the default drive for block
reads and writes. Also if I read the bonnie++ output right, strangely,
block reads seem much slower with a 7-EBS-volume RAID array than with a
single EBS block. RAID helped the writes significantly, though.

Does that make sense? Can anyone help me interpret that output?

All this was on a small instance (which end up with low I/O and CPU priority),
so I guess it's quite possible this test was dominated with people running more
expensive instances stealing the CPU and I/O resources.

Here's the script I just used after attaching 7 EBS volumes to one of my
instances:
================================================================================
sudo mdadm --create /dev/md0 --level=0 --raid-devices=7 /dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb4 /dev/sdb5 /dev/sdb6 /dev/sdb7
sudo mkfs.ext3 /dev/md0
sudo mkdir /mnt/md0
sudo tune2fs -o journal_data_writeback /dev/md0
sudo mount /dev/md0 /mnt/md0
sudo chmod a+w /mnt/md0
cd /mnt/md0
bonnie++ -d /mnt/md0
================================================================================

And here's the output:

================================================================================
= 1 local disk on EC2 small instance
===============================================================================
Version 1.03c ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
ars.forensicl 3408M 21139 35 65132 11 31224 2 24915 19 70138 1 189.1 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
ars.forensiclogic.com,3408M,21139,35,65132,11,31224,2,24915,19,70138,1,189.1,0,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++

================================================================================
= 1 EBS disk on EC2 small instance
===============================================================================

Version 1.03c ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
ars.forensicl 3408M 22239 34 40111 5 17178 0 23539 17 51379 0 570.1 0
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
ars.forensiclogic.com,3408M,22239,34,40111,5,17178,0,23539,17,51379,0,570.1,0,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++

================================================================================
= RAID0 of 7 EBS disks on EC2 small instance
===============================================================================

Version 1.03c ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
ars.forensicl 3408M 20884 34 115135 24 17586 1 15472 20 23198 0 5659 1
------Sequential Create------ --------Random Create--------
-Create-- --Read--- -Delete-- -Create-- --Read--- -Delete--
files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP
16 +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++ +++++ +++
ars.forensiclogic.com,3408M,20884,34,115135,24,17586,1,15472,20,23198,0,5659.1,1,16,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++,+++++,+++