IceWarp is almost completely database-driven with the main exception of the actual mail files themselves. In larger mail stores this can lead to a higher disk I/O as the mailboxes are being loaded through various services. Along with the actual mail file itself, there are other files such as the index file, flags file, and others that keep track of the mailbox and message properties. Each of these files can be opened in a single IMAP call when retrieving mail and folders or loading the account. On a busy server, this can add up and potentially cause performance decreases since the disk I/O is higher than normal.
To combat this possibility we implemented the "Small Files Cache" so the calls would no longer call the disk directly and instead just receive the data from memory. For increased performance, it is recommended to use the cache if you have at least 8GB of memory on the server. To enable small files caching please follow the steps below.
1. Open the administration console
2. Go to [File, API Console]
3. In the search field type "smallfiles".
4. In the "smallfilescache.size" value field double-click and now enter the amount of memory you wish to allocate for this cache in Bytes.
** We recommend 1GB for low-loaded server ** and ** 4 GB to high-loaded server **
5. Smallfilecache.Maxsize - This will be the maximum allowed size of any file to be cached in Bytes.
** We recommend 3MB for low-loaded server ** and ** 24 MB for high-loaded server **
6. You then can save the changes by pressing OK.
Once the settings are saved you should restart your SMTP service to apply the changes. Once this is done you will no longer be calling these mailbox files directly and instead will be pulling the data from memory.
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