[Gluster-users] Strange errors reading/writing/editing/deleting JPGs, PDFs and PNG from PHP Application

Anand Avati anand.avati at gmail.com
Fri Jun 10 07:43:35 PDT 2011


Do you find anything in the client logs?

On Fri, Jun 10, 2011 at 3:20 AM, Alan Zapolsky <alan at droptheworld.com>wrote:

> Hello,
>
> I have a PHP web application that uses Gluster to store its files.
> There are a few areas of the application that perform multiple
> operations on small to medium size files (such as .jpg and .pdf files)
> in quick succession.  My dev environment does not use Gluster and had
> no problems - but in production, I am seeing some strange errors and
> am wondering if perhaps Gluster could be the cause.
>
> Example 1: I may perform the following sequence of operations on a
> batch of 3,000 photos:
>
> 1. Copy the photo from remote URL to a temp folder
> 2. Create a unique directory based on that photo_id
> 3. Move the photo from the temp dir to the new dir
> 4. Create a medium (1000px), small (250px), and tiny (72px) versions
> of the photo and save them to the temp dir.
>
> Example 2: Turning a PDF to a PNG
>
> 1. Create a PDF document, ranging from a few MB to tens of MB or more.
> 2. Use Ghostscript to read a specific page and create a temp .png file from
> it.
> 3. Use Imagemagick to resize the .png and add a drop shadow.
> 4. Delete the temp .png file
>
> In example 1, I am finding that some of the resulting JPG files wind
> up being corrupted - when attempting to read the problematic JPGs, I
> receive messages such as "bad Huffman code" or "premature end of data
> segment".
>
> In example 2, I am getting strange errors on step 3 - it sometimes has
> a problem finding the file created by step 2.  And then on step 4, I
> sometimes get an error that really baffles me - a line of PHP code
> such as:
>
>   if (is_file($file)) unlink($file);
>
> .. will sometimes produce an error "unlink: no such file or
> directory".  I have no idea how it passes the is_file() check and then
> unlink() says it's not there.
>
> At this point I'm just wondering if Gluster could be the culprit for
> any of this strange behavior, considering the types of operations and
> file sizes I'm working with.  I've included my Gluster volume info
> below.
>
> Thanks for the help.
>
> - Alan
>
> Gluster Volume Info
> [alan at file1:10.X.X.X:d1]$ sudo cat info
> type=2
> count=2
> status=1
> sub_count=2
> version=1
> transport-type=0
> volume-id=3fc69046-a324-42de-bf8a-e1bd2e6e45ab
> brick-0=10.X.X.X:-data-d1
> brick-1=10.Y.Y.Y.38:-data-d1
> performance.cache-size=1024MB
> performance.write-behind-window-size=4MB
> performance.io-thread-count=8
> [alan at file1:10.X.X.X:d1]$
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