Re: Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-04 Thread smaugadi
Dear Adrian and Heinz, Sorry for the delayed replay and thanks for all the help so far. I have tried changing the file system (ext2 and ext3), changed the partitioning geometry (fdisk -H 224 -S 56) as I read that this would improve performance with SSD. I tried ufs, aufs and even coss (downgrade

Re: Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-04 Thread Adrian Chadd
How much disk IO is going on when the CPU shows 70% IOWAIT? Far too much. The CPU time spent in CPU IOWAIT shouldn't be that high. I think you really should consider trying an alternative disk controller. adrian 2009/8/4 smaugadi a...@binat.net.il: Dear Adrian and Heinz, Sorry for the

Re: Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-04 Thread smaugadi
Dear adrian, i will try an alternative disk controller and update the result. Regards, Adi. Adrian Chadd-3 wrote: How much disk IO is going on when the CPU shows 70% IOWAIT? Far too much. The CPU time spent in CPU IOWAIT shouldn't be that high. I think you really should consider trying an

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread smaugadi
Dear Adrian, During the implementation we encountered issues with all kind of variables such as: Limit of file descriptors (now the squid is using 204800). TCP port range was low (increased to 1024 65535) TCP timers (changed them) The ip_conntrack and hash size were low (now 524288 262144

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread Adrian Chadd
2009/8/2 smaugadi a...@binat.net.il: Dear Adrian, During the implementation we encountered issues with all kind of variables such as: Limit of file descriptors (now the squid is using 204800). TCP port range was low (increased to 1024 65535) TCP timers (changed them) The ip_conntrack and

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread Waitman Gobble
smaugadi wrote: Dear ALL, We have a squid server with high volume of traffic, 200 – 300 MB. The server is in transparent mode and using 18GB of ramdisk. With this configuration performance is very good (after optimizing the squid and the linux machine). The problem is the small size of cache

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread smaugadi
Dear Adrian, Well my conclusion that this is an IO problem came from the fact that I see huge IO waits as the volume of traffic increase (with tools such as mpstat), when using ramdisk there is no such issue. I have configured the SSD drive with ext2, no journal, noatime. Used the “noop” I/O

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread smaugadi
Dear Waitman, Testing the SSD drive, before installing it on the squid, showed huge performance advantage in IOPS, read/write. So, I thought that this will solve the problems I had with HDD. But it was not so, look at this output: 12:39:35 PM CPU %user %nice%sys %iowait%irq %soft

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread Adrian Chadd
Are you seeing high IO wait CPU use, or high IO wait times on IO? Adrian 2009/8/2 smaugadi a...@binat.net.il: Dear Adrian, Well my conclusion that this is an IO problem came from the fact that I see huge IO waits as the volume of traffic increase (with tools such as mpstat), when using

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread Adrian Chadd
Well, from what I've read, SSDs don't necessarily provide very high random write throughput over time. You should do some further research into how they operate to understand what the issues may be. In any case, the much more important information is what IO pattern(s) are occuring on your

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread smaugadi
Well I'm seeing that the CPU is taking a lot of time waiting for outstanding disk I/O request. Adi Adrian Chadd-3 wrote: Are you seeing high IO wait CPU use, or high IO wait times on IO? Adrian 2009/8/2 smaugadi a...@binat.net.il: Dear Adrian, Well my conclusion that this is an

Re: [squid-users] Squid high bandwidth IO issue (ramdisk SSD)

2009-08-02 Thread Adrian Chadd
Generally large amounts of CPU being spent in IO wait means that the driver is not well-written or the hardware requires extra upkeep to handle IO operations. What hardware in particular are you using? This was one of those big differences between IDE and SATA in the past btw. At least under