[MikeDVB]

Hello!

LiteSpeed Technologies has officially released version 4.1 of their web server software and with it comes full AIO (asynchronous I/O). It's a rather complicated feature and would be hard for me to explain to somebody familiar with web servers in general.

Now I want to put how much of a benefit this new feature is into perspective... We recently had issues with our Cypress server where during R1Soft backups or cPanel backups all websites would become virtually unresponsive and I actually sent out an open letter to all customers on the Cypress server (read it here). We upgraded LiteSpeed to version 4.1 on the Cypress server and enabled AIO support and then we began testing the server to see what kind of effect the new AIO would have on site performance under heavy load.

Not only are we currently running a full R1Soft block scan of the server but we're also simultaneously running a cPanel backup of a rather large account and there is virtually no impact on site loading speed what-so-ever. This is an amazing development and we've rolled this feature out to all servers.

What this means for you:

• Backups can be performed any time, day or night, without dramatically affecting server performance. We do still however ask that you take your regular backups during off-peak times.
  
• That our daily R1Soft backups that protect your data against hardware failure and other forms of data loss will not impact your site performance.

If you have any questions at all about this, do respond to this thread

[frankacter]

Will this be made available to VPS customers?

[MikeDVB]

frankacter, on 17 April 2011 - 05:41 AM, said:

Will this be made available to VPS customers?

We are going to be upgrading VPS to 4.1 however I don't know that AIO would be helpful in a VPS environment (we'd need to test).

[frankacter]

Regarding AIO, thinking that those of us that make use of disk based caching (ala WP SuperCache) would benefit from the improved disk disk I/O performance handling. That being said, the "All bug fixes in 4.0.x branch have been included." is always a plus :-)

For those interested, here is the full changelog for LiteSpeed 4.1:

Quote

*Added support for AIO (Asynchronized disk I/O) to greatly improve performance for servers with heavy Disk I/O.
* Added support for HTTPS SNI (Server Name Indication), allowing multiple secured sites sharing one IP.
* Added support for mod_security 2.5 rule sets.
* Added connection level detailed status in real-time status page of web admin console.
* Compatible with upload progress bar.
* Added support for H.264 streaming.
* Reduced memory usage when thousands of virtual hosts configured through Apache httpd.conf.
* All bug fixes in 4.0.x branch have been included.

[MikeDVB]

We've seen highly dynamic php+mysql driven sites remain fast and responsive even under very heavy disk load with aio where as without it - they would have slowed to a crawl.

I have to say I'm very impressed.

[TotalZen]

That's fantastic news

Hopefully performance increases even more once CloudLinux fixes their I/O issues in a future release.

[MikeDVB]

TotalZen, on 18 April 2011 - 09:00 AM, said:

That's fantastic news

Hopefully performance increases even more once CloudLinux fixes their I/O issues in a future release.

It's less of an I/O issue and more of overhead from the UBC system (the one that is supposed to limit the RAM per LVE). We never used the LVE Memory limits however until recently there was no option to disable them. We're just waiting on CloudLinux to give us the go-ahead for stability on the newest version before we switch over.

[TotalZen]

MikeDVB, on 19 April 2011 - 02:26 AM, said:

It's less of an I/O issue and more of overhead from the UBC system (the one that is supposed to limit the RAM per LVE). We never used the LVE Memory limits however until recently there was no option to disable them.

Ah so that's the specific problem then, thanks for clarifying.

[MikeDVB]

TotalZen, on 19 April 2011 - 03:09 AM, said:

Ah so that's the specific problem then, thanks for clarifying.

No problem!

[RSyvarth]

Has this already been implemented across all of the servers? Because it seems like Fresco is still having downtimes around midnight every night...

[MikeDVB]

RSyvarth, on 24 April 2011 - 12:30 AM, said:

Has this already been implemented across all of the servers? Because it seems like Fresco is still having downtimes around midnight every night...

It was, until last night due to an issue we're having with 4.1 which you can see here:
LiteSpeed 4.1 Spinlock? - LiteSpeed Technologies Forums

While AIO was on, the backup process was not causing any slowdowns during the backup process (which runs from around 12:30 AM to around 1:30 AM EST GMT-5) on Fresco but with it off, during this time, things will be a little sluggish.

Beyond that, we're not picking up any downtime or issues so if you are having any, by all means, open a ticket and provide as much information as possible.

[MikeDVB]

LiteSpeed Technologies has gotten back with us that they believe the issue is resolved and we've updated to the latest build of the software and re-enabled this very great feature.

[MikeDVB]

We've been running 4.1 again with AIO since my last post on the 25th with no issues. Yay!