From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <1353946374.82746.YahooMailClassic@web184406.mail.bf1.yahoo.com> Date: Mon, 26 Nov 2012 08:12:54 -0800 From: "Brian L. Stuart" To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [9fans] growing/shrinking venti arena files -OR- arena file format Topicbox-Message-UUID: e528600c-ead7-11e9-9d60-3106f5b1d025 > I'm wondering if anyone can shed some light on growing=0A> and/or shrinki= ng arena files (i.e., disk partitions).=A0=0A> With the growing popularity = of logical volume management,=0A> vitrualization, etc., resizing partitions= is becoming=0A> more and more common, and many file systems already=0A> ha= ve "resize" tools or options to grow/shrink file=0A> system structures acco= rding to changes in the size of=0A> the underlying device.=A0 I'm wondering= what capacities=0A> (if any) venti has for dealing with inceases or=0A> de= cresases in the size of its arena files.=0A=0ATo make sure I understand the= question I'll attempt=0Ato rephrase it.=A0 If I have a logical volume cont= aining=0Aan arena partition and I resize that volume to a=0Alarger size, is= there a way to make venti aware of=0Athe larger partition and format the a= dditional space=0Aas arenas in the same partition?=A0 If I have understood= =0Athe question correctly, I don't think any of the existing=0Autilities wi= ll do that.=A0 In principle, it should be=0Apossible, assuming that you don= 't add so much that=0Athe arena map won't fit into the fixed 512K map that= =0Afmtarenas creates.=A0 Fmtarenas just writes a partition=0Aheader and the= n loops through all the arenas calling=0Anewarena.=A0 You could probably up= date the partition=0Aheader and call newarena for each arena in the new=0As= pace.=A0 There are probably some gotchas that I'm overlooking=0Aat the mome= nt, but that would be the place I'd start.=0A=0A> Yes, I know that the cano= nical way to add more storage to a=0A> venti server is to format and add an= ADDITIONAL arena file=0A> with venti/fmtindex -a.=0A=0AI'd be inclined to = think this is easier and safer=0Athan munging around with an existing arena= partition.=0A=0A> Is there a TECHNICAL SPECIFICATION for the arena file=0A= > format?=0A=0AThe source code would the be most accurate spec on the=0Afor= mat.=A0 I'd suggest starting with src/venti/srv/dat.h=0Aand move on to look= at fmtarenas.c.=A0 Calls in it will=0Alead you to the other files that wil= l be interesting.=0A=0A> For that matter, any formal specifications for 9P2= 000=0A=0ASection 5 of the man pages is the best reference for=0Athis.=0A=0A= > venti protocol would be very helpful, too (for other=0A> purposes).=0A=0A= The sources are the best place to look for this one=0Atoo.=0A=0ABLS=0A