6/17/2023 0 Comments Website file storageGluster is one of the most popular options for file storage, and in particular file storage in cloud deployments (discussed in the next chapter). During an rsync from point A to point B, how do you differentiate between a file having not yet been synced and a file having been deleted? Issues like this are why “just using rsync” is becoming less of an answer to this problem. For example, there is no clear method for removing files from web nodes where the file removal did not originally take place. Because of this, session affinity is usually a requirement as it “resolves” the issue by ensuring that a user who uploads an avatar remains on the webnode he uploaded it on.Įven if you are entirely fine with having session affinity enabled and with the synchronization delay, there are other complications. Having a missing user avatar during the sync delay for some users is a problem, but having the user who uploaded that avatar not able to see it on his own profile page is a critical problem. Additionally, this configuration virtually requires session affinity. It must be acceptable to have broken links on pages during this sync delay. First, there will always be some sort of delay in file syncing. In this configuration, you would simply set up rsync processes between your web nodes to ensure that every file on webnode1 is also on webnode2, webnode3, and so on. The first option we should consider is, at first glance, the simplest. In this chapter, we will discuss some of the more popular methods for Drupal deployments and their various advantages and disadvantages. Now that we understand why this is important, we can cover a few different methods of maintaining this consistency when using multiple web nodes. It is easy to forget how important coherent file storage is to a functional website. Keep this in mind while debugging “strange issues” that may come up on your infrastructure (certain users not seeing CSS correctly, 404s on only certain web nodes, etc.). Even if your site doesn’t accept user uploads, Drupal creates its own JS/CSS aggregate files on disk, and if those don’t exist on both web nodes, you will quickly hit issues on the web node without them. If there is a delay in that file becoming available on webnode2-or worse, if its not synchronized at all-users will start seeing broken image links for that file. That user’s avatar is written to disk on webnode1. Why is this important? Imagine that a user goes to your site and uploads an avatar. However, the complication of ensuring your static files are synchronized between web nodes is often overlooked. Ensuring your file storage is coherent and synchronized between your web nodes is often the redheaded stepchild of infrastructure design-most everyone is aware that you need all your web nodes to agree on database information, and quite a few know that your object cache needs to be coherent. In this chapter, we will discuss the options for file storage in infrastructures with multiple web nodes. Chapter 10. File Storage for Multiple Web Servers
0 Comments
Leave a Reply. |