From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755855Ab2FDS71 (ORCPT ); Mon, 4 Jun 2012 14:59:27 -0400 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:64868 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752392Ab2FDS7Z (ORCPT ); Mon, 4 Jun 2012 14:59:25 -0400 Message-ID: <4FCD0591.2050504@gmail.com> Date: Mon, 04 Jun 2012 22:59:29 +0400 From: George Shuklin User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:10.0.4) Gecko/20120510 Icedove/10.0.4 MIME-Version: 1.0 To: Casey Schaufler CC: Al Viro , linux-kernel Subject: Re: Why minor is still 8 bit? References: <4FCC0E6D.9000206@gmail.com> <20120604013504.GU30000@ZenIV.linux.org.uk> <4FCC3151.1040503@gmail.com> <4FCCDE2B.3020306@schaufler-ca.com> In-Reply-To: <4FCCDE2B.3020306@schaufler-ca.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04.06.2012 20:11, Casey Schaufler wrote: > On 6/3/2012 8:53 PM, George Shuklin wrote: >> On 04.06.2012 05:35, Al Viro wrote: >>> On Mon, Jun 04, 2012 at 05:25:01AM +0400, George Shuklin wrote: >>>> I've understand that major and minor numbers for device is 8-bit size. >>>> >>>> I've don't understand, WHY? In 2012! >>>> >>>> (I've just have some discussion about 8-bit counter limitations in >>>> context of cloud computing. In middle of 2012!!!!) >>> Yes, shocking. It's been several years and you are still using that >>> buzzword; I mean, it's _so_ 2010... Should've moved on to whatever's >>> in this year... >>> >>> Incidentally, minors are 20 bit and majors are 12, but don't let that >>> stand in the way of righteous indignation - what's mere facts when >>> one is having discussions in context, presumably leveraging synergies >>> all along... >> Ok, thank you for information. >> >> But question is almost same: can I have 30k active logical volumes on >> my single server, please? > What are you trying to do, create a logical volume for every file? > There are at least three separate technologies available that will > solve whatever your problem is better than having 30,000 logical > volumes. I don't have a clue what you think you're trying to > accomplish and I am still willing to bet beers that you're bus is > parked solidly on the wrong tracks. > > Very simple sample: I'd like to create shared storage to publish volumes via ISCSI. ~60Tb of drives, ~2Gb average disk size = 30k disk images. Can I just create a bunch of LV and export them by iet or scst? Nope: There is a serious limit for amount of active LV per host. Yes, I can create filesystem, put images (as file) to that filesystem and publish them back, but why FS is needed to do such simple task?