FetchError

[David Lachapelle]

Hi All,

I've been seeing weird behavior on and off recently on our  varnish install and not sure whats going on, it would seem we're getting random FetchErrors:

> FetchError   c chunked read_error: 0


Which is resulting in a 503 being returned to the end user.  This seems to only happen once, and then on a refresh of the page, it loads correctly.  We do have multiple apache backends, so I thought it might be a particular backend causing problems, so we put a restart in our vcl_error, but that still doesn't seem to help things along.

I've confirmed we have mod_deflate disabled in apache and we're even stripping out the accept encoding in our VCL (sub vcl_recv)

>         remove req.http.Accept-Encoding;


Here's an excerpt from our varnishlog:

>   135 RxRequest    c GET
>   135 RxURL        c xxxxxxx
>   135 RxProtocol   c HTTP/1.1
>   135 RxHeader     c Accept: image/gif, image/jpeg, image/pjpeg, application/x-ms-application, application/vnd.ms-xpsdocument, application/xaml+xml, application/x-ms-xbap, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword, application/x-shockwave-fla
>   135 RxHeader     c Referer: xxxxxxx
>   135 RxHeader     c Accept-Language: en-ca
>   135 RxHeader     c User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.0; Trident/4.0; SLCC1; .NET CLR 2.0.50727; .NET CLR 3.5.30729; InfoPath.2; .NET CLR 3.0.30729; .NET4.0C; OfficeLiveConnector.1.5; OfficeLivePatch.1.3)
>   135 RxHeader     c Accept-Encoding: gzip, deflate
>   135 RxHeader     c Host: xxxxxxx
>   135 RxHeader     c Connection: Keep-Alive
>   135 RxHeader     c Cookie: xxxxxxx
>   135 VCL_call     c recv lookup
>   135 VCL_call     c hash hash
>   135 VCL_call     c miss fetch
>   135 Backend      c 146 loadbalancer APP_7
>   135 TTL          c 1763959069 RFC 5 1285264818 0 0 0 0
>   135 VCL_call     c fetch
>   135 TTL          c 1763959069 VCL 31536000 1285264818
>   135 VCL_return   c deliver
>   135 ObjProtocol  c HTTP/1.1
>   135 ObjStatus    c 200
>   135 ObjResponse  c OK
>   135 ObjHeader    c Date: Thu, 23 Sep 2010 18:00:18 GMT
>   135 ObjHeader    c Server: Apache/2.2.14 (Ubuntu)
>   135 ObjHeader    c X-Powered-By: PHP/5.3.2-1ubuntu4.2
>   135 ObjHeader    c Content-Type: text/html; charset=utf-8
>   135 FetchError   c chunked read_error: 0

>   135 VCL_call     c error restart
>   135 VCL_call     c recv lookup
>   135 VCL_call     c error deliver
>   135 Length       c 52
>   135 VCL_call     c deliver deliver
>   135 TxProtocol   c HTTP/1.1
>   135 TxStatus     c 503
>   135 TxResponse   c Service Unavailable
>   135 TxHeader     c Server: Varnish


Anyone have any ideas?

Dave
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