From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4AAE663F.1080207@0x6a.com> Date: Mon, 14 Sep 2009 10:50:23 -0500 From: Jack Norton User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [9fans] Petabytes on a budget: JBODs + Linux + JFS Topicbox-Message-UUID: 6e8fe872-ead5-11e9-9d60-3106f5b1d025 erik quanstrom wrote: >> So what about having venti on an AoE device, and fossil on a local drive >> (say an ssd even)? >> > > sure. we keep the cache on the coraid sr1521 as well. > > >> How would you handle (or: how would venti handle), a >> resize of the AoE device? >> > > that would depend on the device structure of ken's fs. > as long as you don't use the pseudo-worm device, it wouldn't > care. the worm would simply grow. if you use the pseudo-worm > device (f), changing the size of the device would fail since > the written bitmap is at a fixed offset from the end of the > device. and if you try to read an unwritten block, the f > panics the file server. i stopped using the f device. > > - erik > > I am going to try my hands at beating a dead horse:) So when you create a Venti volume, it basically writes '0's' to all the blocks of the underlying device right? If I put a venti volume on a AoE device which is a linux raid5, using normal desktop sata drives, what are my chances of a successful completion of the venti formating (let's say 1TB raw size)? Have you ever encountered such problems, or are you using more robust hardware? I ask because I have in the past, failed a somewhat-used sata drive while creating a venti volume (it subsequently created i/o errors on every os I used on it, although it limped along). I must say it is quite a brutal process, creating venti (at least I get that impression from the times I have done it in the past). If linux is my raid controller, I know that it is _very_ picky about how long a drive takes to respond and will fail a drive if it has to wait too long. By the way I am currently buying a few pieces of cheap hardware to implement my own diskless fileserver. Should be ready to go in about a couple of weeks. -Jack