Hello list, I'm very sorry, what i've forward mail it to linux-mm list, but i can't find any mailing list like linux-block-io or something like that %) I've recently find rapid cache and it confuse me, as i know, linux use almost all free ram for IO caching and do it very cool and fast. May be i misstake in something? May be linux memory io cache sub system not fast as i think? ---------- Forwarded message ---------- From: Petros Koutoupis <pkoutoupis@xxxxxxxxxxxxxxxxxx> Date: 2015-06-11 18:33 GMT+03:00 Subject: Re: Why rapiddisk cache, better then build-in ram cache? To: Timofey Titovets <nefelim4ag@xxxxxxxxx> Копия: support@xxxxxxxxxxxxxxxxxx Timofey, Thank you very much for you interest in the project. Linux does not have a built block I/O cache. All block I/O resides in a temporary buffer until the schedular schedules the task to the block device; that is, unless you are running Direct I/O in which all I/O is immediately dispatched regardless of the schedular. Now a file system will cache data in the VFS layer but this cache is somewhat small and limited. With RapidDisk / RapidCache, you can easily enable 1GB or even 1TB of cache to a slower block device, thus enabling a block based cache. Or you can simply just enable a large RAM based block device and not use it as a cache. I guess it all depends on your requirements. You are correct, though. This should be detailed on the Wiki and I will definitely address it. Thank you for bringing it to our attention. On Thu, Jun 11, 2015 at 10:26 AM, Timofey Titovets <nefelim4ag@xxxxxxxxx> wrote: > > Hello, > i've read http://rapiddisk.org/index.php?title=Main_Page > That a very cool, > but i can't understand why it better than linux built in file/block io cache? > > May be you can explain it on wiki page? > > -- > Have a nice day, > Timofey. -- Petros Koutoupis Inverness Storage Solutions, LLC 312-854-9707 pkoutoupis@xxxxxxxxxxxxxxxxxx -- Have a nice day, Timofey. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href