I am running a Codeigniter application that uses page cache with ~350k files and take up ~26Gb of disk space in ONE folder. Is that too much?
If memory serves, CI puts each page cache in a single folder. Assuming you are a FAT32 Linux machine, and the files aren't grouped into sub-folders I imagine you may be taking a performance hit.
Referencing this; How many files can I put in a directory?
A reasonable solution could be to override the default caching library to group things into folders (perhaps based on the first N of the hash name) to improve performance.
Related
I have a php web application which has a gallery.
This gallery uses justified javascript.
Then it uses timthumb.php to resize the images without saving the images in the server.
i would like to know which one would be better..
Loading all the images using timthumb.php
Or saving resized images in the server cache folder and loading all
the images from the cache folder.
I have tried these two methods. Strangely 2nd method is slower than first for the first load.
Thank you for all the help.
Lynn
Timthumb tends to have security issues and either way image processing requires a great deal of RAM so having cache folders is the best option. Notice that I said folders and not a cache folder. On IIS servers or any windows based server you will run into slowness accessing folders which have more than a few thousand files. Linux is known to have the same problem but not until you have a few hundred thousand files in a folder. Either way, if you're dealing with millions of images it is best to categorize them in some way into separate folders so you don't end up with slowdowns from the OS trying to locate the file.
Honestly I do not have much idea about timthumb.php.
Although saving the photos in a server cached folder seems to be a better idea, You can save the save the path of the image in your datasource (normally a relational database) , and then while retrieving the photos , extract it from cached folder.
It might be a possibility that your cache is getting reloaded time and again and thats why taking sometime in the first load.
I'm building website with billions of images. I'm little confused to store images in single directory. how many images can be stored in single directory. or it slow down the server ?
Have you considered object storage such as AWS S3? http://aws.amazon.com/s3/
As for performance, I think it depends on the file system you intend to use. Some file systems index directory content in a linear manner, others use more efficient algorithms. It also depends whether any of your system services will need to scan the directory regularly.
I found this: http://events.linuxfoundation.org/slides/2010/linuxcon2010_wheeler.pdf
In this question: https://serverfault.com/questions/43133/filesystem-large-number-of-files-in-a-single-directory
I made a dynamic site that has over 20,000 pages and once a page is created there is no need to update it for at-least one month or even a year. So I'm caching every page when it is first created and then delivering it from a static html page
I'm running a php script (whole CMS is on PHP) if (file_exists($filename)) to first search for the filename from the url in cache-files directory and if it matches then deliver it otherwise generate the page and cache it for latter use. Though it is dynamic but still my url does not contain ?&=, I'm doing this by - and breaking it into array.
What I want to know is will it create any problem to search for a file from that huge directory?
I saw a few Q/A like this where it says that there should not be problem with number of files I can store on directory with ext2 or ext3 (I guess my server has ext3) file system but the speed of creating a new file will decrease rapidly after there are files over 20-30,000.
Currently I'm on a shared host and I must cache files. My host a soft limit of 100,000 files in my whole box which is good enough so far.
Can someone please give me any better idea about how to cache the site.
You shouldn't place all of the 20K files in a single directory.
Divide them into directories (by letter, for example), so you access:
a/apple-pie-recipe
j/john-doe-for-presidency
etc.
That would allow you to place more files with less constraints on the file-system, which would increase the speed. (since the FS doesn't need to figure out where your file is in the directory along with other 20k files, it needs to look in about a hundred)
there should not be problem with number of files I can store on directory with ext2 or ext3
That's rather an old document - there are 2 big differences between ext2 and ext3 - journalling is one, the other is H-TREE indexing of directories (which reduces the impact of storing lots of files in the same directory). While it's trivial to add journalling to an ext2 filesystem and mount it as ext3, this does not give the benefits of dir_index - this requires a full fsck.
Regardless of the filesystem, using a nested directory structure makes the system a lot more manageable and scalable - and avoids performance problems on older filesystems.
(I'm doing 3 other things since I started writing this and see someone else has suggested something similar - however Madara's approach doesn't give an evenly balanced tree, OTOH having a semantic path may be more desirable)
e.g.
define('GEN_BASE_PATH','/var/data/cache-failes');
define('GEN_LEVELS', 2);
function gen_file_path($id)
{
$key=md5($id);
$fname='';
for ($x=0; $x<=GEN_LEVELS; $x++) {
$fname=substr($key, 0, 1) . "/";
$key=substr($key,1);
}
return GEN_BASE_PATH . "/" . $fname . $key;
}
However the real way to solve the problem would be to serve the content with the right headers and run a caching reverse proxy in front of the webserver (though this isn't really practical for a very lwo volume site).
I've got nearly a million images for my site and they are stored in one folder on my windows server.
Since opening this folder directly on desktop drive me and my CPU crazy I am wondering that whether fetching one of them using my PHP script for a HTTP request is also laborious. So, will separating them into different folders improve the performance?
No, the performance does not depend on the number of files that are in a directory. The reason why opening the folder in Windows explorer is slow is because it has to render icons and various other GUI related things for each file.
When the web server fetches a file, it doesn't need to do that. It just (more or less) directly goes to the location of the file on the disk.
EDIT: Millions is kind of pushing the limits of your file system (I assume NTFS in your case). It appears that anything over 10,000 files in a directory starts to degrade your performance. So not only from a performance standpoint, but from an organizational standpoint as well, you may want to consider separating them into subdirectories.
Often the best answer in a case like this is to benchmark it. It shouldn't be too hard to create a program that opens 1000 hard-coded file names and closes them. Run the test on your million-plus directory and another directory containing only those 1000 files being tested and see if there's a difference.
Not only does the underlying file system make a difference, but accessing over a network can affect the results too.
Separating your files into seperate directories will most likely help performance. But as mark suggests it's probably worth benchmarking
I develop some PHP project on Linux platform. Are there any disadvantages of putting several thousand images (files) in one directory? This is closed set which won't grow. The alternative would be to separate this files using directory structure based on some ID (this way there would be let's say only 100 in one directory).
I ask this question, because often I see such separation when I look at images URLs on different sites. You can see that directory separation is done in such way, that no more then several hundreds images are in one directory.
What would I gain by not putting several thousand files (of not growing set) in one directory but separating them in groups of e.g. 100? Is it worth complicating things?
UPDATE:
There won't be any programmatic iteration over files in a directory (just a direct access to an image by it's filename)
I want to emphasize that the image set is closed. It's less then 5000 images, and that is it.
There is no logical categorization of this images
Human access/browse is not required
Images have unique filenames
OS: Debian/Linux 2.6.26-2-686, Filesystem: ext3
VALUABLE INFORMATION FROM THE ANSWERS:
Why separate many files to different directories:
"32k files limit per directory when using ext3 over nfs"
performance reason (access speed) [but for several thousand files it is difficult to say if it's worth, without measuring ]
In addition to faster file access by separating images into subdirectories, you also dramatically extend the number of files you can track before hitting the natural limits of the filesystem.
A simple approach is to md5() the file name, then use the first n characters as the directory name (eg, substr(md5($filename), 2)). This ensures a reasonably even distribution (vs taking the first n characters of the straight filename).
usually the reason for such splitting is file system performance.
for a closed set of 5000 files I am not sure it's worth the hassle.
I suggest that you try the simple approach of putting all the files in one directory thing, but keep an eye open on the actual time it takes to access the files.
if you see that it's not fast enough for your needs, you can split it like you suggested.
I had to split files myself for performance reasons.
in addition I bumped into a 32k files limit per directory when using ext3 over nfs (not sure if it's a limit of nfs or ext3).
so that's another reason to split into multiple directories.
in any case, try with a single dir and only split if you see it's not fast enough.
There is no reason to split those files into multiple directories, if you won't expect any filename conflicts and if you don't need to iterate over those images at any point.
But still, if you can think of a suggestive categorization, it's not a bad idea to sort the images a bit, even if it is just for maintenance reasons.
I think there is two aspects to this question:
Does the Linux file system that you're using efficiently support directories with thousands of files. I'm not an expert, but I think the newer file systems won't have problems.
Are there performance issues with specific PHP functions? I think direct access to files should be okay, but if you're doing directory listings then you might eventually run into time or memory problems.
The only reason I could imagine where it would be detrimental was when iterating over the directory. More files, means more iterations. But that's basically all I can think of from a programming perspective.
Several thousand images are still okay. When you access a directory, operating systems reads the listing of its files by blocks of 4K. If you have plain directory structure, it may take time to read the whole file listing if there are many (e. g. hundred thousand) files in it.
If changing the filesystem is an option, I'd recommend moving wherever you store all the images to a ReiserFS filesystem. It is excellent at fast storage/access of lots of small files.
If not, MightyE's response of breaking them into folders is most logical and will increase access times by a considerable margin.