Over 66 seconds to fetch a simple css file on IIS 6. Help please

am 14.01.2008 02:50:01 von unknown

I've been struggling with this for weeks now and can't find the problem for
the life of me. When accessing pages on my Web site, sometimes it's very
responsive and sometimes it takes a very long time. It doesn't seem to be
database related, because even simple files, such as robots.txt sometimes
take over a minute to returnHere are some details:

- I visit a page with my browser and notice it's taking some time. While
waiting for the page to return, I open another browser and hit the same page
and it returns quickly. So, while browser 1 is still waiting for a response,
browser 2 get a very quick response for the same page. Eventually, 60 seconds
or so later, browser 1 gets the page.

- I checked the IIS log files to make sure it's not a network issue. It's
not. IIS logs report the extremely long times it's taking to respond.

- While waiting for a slow page to load, I use terminal services to log in
to the server and check perfmon, performance is less than 5%, and the machine
is very responsive.

- There are no errors in the event log or the iis httperror files.

- The problem happens randomly, and it affects all kinds of files, weather
static (.txt,.css,.png) or dynamic (.aspx,asmx). Hitting the same page again,
gives a quick reply right away.

I'm using IIS6 on Windows Server 2003. It's a virtual host (vps). I'm using
..net 2.0, although the problem doesn't seem to be related to .net.

Any help is greatly appreciated.

Thanks,
Waleed

Re: Over 66 seconds to fetch a simple css file on IIS 6. Help please

am 14.01.2008 07:16:16 von David Wang

On Jan 13, 5:50=A0pm, Waleed ninua com> wrote:
> I've been struggling with this for weeks now and can't find the problem fo=
r
> the life of me. When accessing pages on my Web site, sometimes it's very
> responsive and sometimes it takes a very long time. It doesn't seem to be
> database related, because even simple files, such as robots.txt sometimes
> take over a minute to returnHere are some details:
>
> - I visit a page with my browser and notice it's taking some time. While
> waiting for the page to return, I open another browser and hit the same pa=
ge
> and it returns quickly. So, while browser 1 is still waiting for a respons=
e,
> browser 2 get a very quick response for the same page. Eventually, 60 seco=
nds
> or so later, browser 1 gets the page.
>
> - I checked the IIS log files to make sure it's not a network issue. It's
> not. IIS logs report the extremely long times it's taking to respond.
>
> - While waiting for a slow page to load, I use terminal services to log in=

> to the server and check perfmon, performance is less than 5%, and the mach=
ine
> is very responsive.
>
> - There are no errors in the event log or the iis httperror files.
>
> - The problem happens randomly, and it affects all kinds of files, weather=

> static (.txt,.css,.png) or dynamic (.aspx,asmx). Hitting the same page aga=
in,
> gives a quick reply right away.
>
> I'm using IIS6 on Windows Server 2003. It's a virtual host (vps). I'm usin=
g
> .net 2.0, although the problem doesn't seem to be related to .net.
>
> =A0 =A0 Any help is greatly appreciated.
>
> Thanks,
> Waleed

What do you mean by "it's a virtual host". Are you saying this server
is in a "Virtual Machine" instead of the usual "Physical Machine"?

If so, then it is very possible that *everything* looks perfect in the
Virtual Machine, but the physical host has performance issues, in
which case whatever is running in the Virtual Machine just takes a
long time for "no good reason".

You can also turn on ETW tracing in IIS6 to determine exactly where
all the time is being spent for every request. I suspect it will show
that IIS is running very quickly, but something external is taking a
long time. You may find that it's random, in which case I start
looking outside of IIS and at its environment.

//David
http://w3-4u.blogspot.com
http://

Re: Over 66 seconds to fetch a simple css file on IIS 6. Help plea

am 14.01.2008 10:35:01 von unknown

Yes, it's in a virtual machine. My first guess was that it might be a side
effect of other virtual machines on the same server locking some resources
(hard drive?) or something like that. But, I did rule that out, because even
while a request for a certain file is hanging somewhere, if I open another
browser and request the same file, I get a quick response. So, it's as if the
one thread that is handling my first request is stuck somewhere, without
affecting other threads accessing the same file.

Thanks, for the ETW tip. I hadn't known that these tools excited (never
needed this level of debugging before). This is a great tool, I'm setting it
up and I'll report back on what I find. Thanks.

Re: Over 66 seconds to fetch a simple css file on IIS 6. Help plea

am 15.01.2008 00:34:25 von unknown

David,
This is what I got from ETW (I removed irrelevant details to keep it
readable, but kept the titles all events). The main delay (3 seconds, in this
case) is happening between the HTTPSYS_CACHEABLE and NOTIFY_ISAPI_COMPLETION
events. I'm not sure what that means? Is that time spent inside my asp.net
app? Any suggestions on how to drill deeper?

AspNetReq: Start - Start
ConnId: 17059336
Timestamp: 22:00:45.946.969600

IISCache: URL_CACHE_ACCESS_START - IIS starts accessing URL cache to get
metadata
IISGeneral: GENERAL_GET_URL_METADATA - IIS gets URL metadata
IISCache: URL_CACHE_ACCESS_END - IIS ends accessing URL cache
IISCache: URL_CACHE_ACCESS_START - IIS starts accessing URL cache to get
metadata
IISGeneral: GENERAL_GET_URL_METADATA - IIS gets URL metadata
IISCache: URL_CACHE_ACCESS_END - IIS ends accessing URL cache

IISCache: HTTPSYS_CACHEABLE - IIS decides if the request is HTTP.SYS
cacheable
HttpsysCacheable: 0
Reason: URL_CHANGE_BY_FILTER
ContextIDSeq: 9
Timestamp: 22:00:45.966.998400

W3Isapi: NOTIFY_ISAPI_COMPLETION - Notify Isapi of Completion
ContextIDSeq: 9
Timestamp: 22:00:48.320.382400

AspNetReq: End - End
ConnId: 17059336
ContextIDSeq: 9
Timestamp: 22:00:48.320.382400

"David Wang" wrote:

> On Jan 13, 5:50 pm, Waleed ninua com> wrote:
> > I've been struggling with this for weeks now and can't find the problem for
> > the life of me. When accessing pages on my Web site, sometimes it's very
> > responsive and sometimes it takes a very long time. It doesn't seem to be
> > database related, because even simple files, such as robots.txt sometimes
> > take over a minute to returnHere are some details:
> >
> > - I visit a page with my browser and notice it's taking some time. While
> > waiting for the page to return, I open another browser and hit the same page
> > and it returns quickly. So, while browser 1 is still waiting for a response,
> > browser 2 get a very quick response for the same page. Eventually, 60 seconds
> > or so later, browser 1 gets the page.
> >
> > - I checked the IIS log files to make sure it's not a network issue. It's
> > not. IIS logs report the extremely long times it's taking to respond.
> >
> > - While waiting for a slow page to load, I use terminal services to log in
> > to the server and check perfmon, performance is less than 5%, and the machine
> > is very responsive.
> >
> > - There are no errors in the event log or the iis httperror files.
> >
> > - The problem happens randomly, and it affects all kinds of files, weather
> > static (.txt,.css,.png) or dynamic (.aspx,asmx). Hitting the same page again,
> > gives a quick reply right away.
> >
> > I'm using IIS6 on Windows Server 2003. It's a virtual host (vps). I'm using
> > .net 2.0, although the problem doesn't seem to be related to .net.
> >
> > Any help is greatly appreciated.
> >
> > Thanks,
> > Waleed
>
>
> What do you mean by "it's a virtual host". Are you saying this server
> is in a "Virtual Machine" instead of the usual "Physical Machine"?
>
> If so, then it is very possible that *everything* looks perfect in the
> Virtual Machine, but the physical host has performance issues, in
> which case whatever is running in the Virtual Machine just takes a
> long time for "no good reason".
>
> You can also turn on ETW tracing in IIS6 to determine exactly where
> all the time is being spent for every request. I suspect it will show
> that IIS is running very quickly, but something external is taking a
> long time. You may find that it's random, in which case I start
> looking outside of IIS and at its environment.
>
>
> //David
> http://w3-4u.blogspot.com
> http://
>

Re: Over 66 seconds to fetch a simple css file on IIS 6. Help plea

am 15.01.2008 00:36:18 von unknown