Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756923AbbESPTR (ORCPT ); Tue, 19 May 2015 11:19:17 -0400 Received: from 251.110.2.81.in-addr.arpa ([81.2.110.251]:32838 "EHLO lxorguk.ukuu.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756905AbbESPTN (ORCPT ); Tue, 19 May 2015 11:19:13 -0400 Date: Tue, 19 May 2015 16:19:02 +0100 From: One Thousand Gnomes To: Bill Speirs Cc: Rob Landley , Kernel Mailing List Subject: Re: Userspace Block Device Message-ID: <20150519161902.10881f9b@lxorguk.ukuu.org.uk> In-Reply-To: References: Organization: Intel Corporation X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.27; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1315 Lines: 27 > - Write an ndb-server that is essentially a gateway between nbd and > S3/Google. For each nbd request, I translate it into the appropriate > S3/Google request and respond appropriately. > - I'd run the above server on the machine on some port. > - I'd run a client on the same server using 127.0.0.1 and the above > port, providing the nbd block device. > - Go drink a beer as I rack up a huge bill with Amazon or Google And you probably would because the block layer will see a lot of I/O requests that you would really want to process locally, as well as stuff caused by working at the block not file level (like readaheads). You also can't deal with coherency this way - eg sharing the virtual disk between two systems because the file system code isn't expecting other clients to modify the disk under it. Rather than nbd you could also look at drbd or some similar kind of setup where you keep the entire filestore locally and write back changes to the remote copy. As you can never share the filestore when mounted you can cache it pretty aggressively. Alan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/