(Illustration by Gaich Muramatsu)
On Mon, Nov 11, 2002 at 10:19:31AM +0100, Fabrizio Morbini wrote: > Hi, Can Coda handle file with size bigger than 2 Giga? I'm pretty sure it doesn't. And would even go as far as to question whether it is all that useful. Coda uses whole file caching, so you have to wait for the whole file to be fetched, as well as the whole file being written back when it is changed. On a 100Base-T network that will easily take over 4 minutes if everything goes right. Also, the metadata vs. data ratio's in the client will need to be changed. Right now venus assumes a 'normal' distribution with an average filesize of about 16KB per file. So if you set venus up for a multi GB local cache, it will assume you are going to store millions of files. Such large files are in most cases either CD-images or databases, and it is mentioned many times all over the website, Coda Howto, system admin manual, mailinglists that trying to store databases in Coda is not supported. Coda does not provide locking, so any concurrent updates can and will lead to conflicts. Because of the session semantics, updates are not propagated to other clients until the database file is closed, which typical database programs never do because for them it is a waste of performance closing and reopening a file. When a database is only used for reading, the database library/software typically still opens it read/write, because it can avoid reopening in case you decide to modify data after all, as a result Venus automatically assumes that the file has been updated and will write back the file even if nothing was changed. And many more reasons why it is just a bad idea. Databases have their own methods for access across a network and replication. Those methods are tried and tested, if a database doesn't provide ways to replicate it's data, it is probably because it isn't that easy. For CD-images, it is possible to store the actual contents of the image. That way clients can access the data without needing a loopback mount and an isofs image can easily be recreated. JanReceived on 2002-11-11 13:06:05