Date: Sun, 9 Jun 2013 18:09:05 +0400 (MSK) From: Dmitry Morozovsky <marck@rinet.ru> To: Jeremy Chadwick <jdc@koitsu.org> Cc: freebsd-fs@freebsd.org Subject: Re: /tmp: change default to mdmfs and/or tmpfs? Message-ID: <alpine.BSF.2.00.1306091759530.48048@woozle.rinet.ru> In-Reply-To: <20130609124603.GA35681@icarus.home.lan> References: <alpine.BSF.2.00.1306091538490.48048@woozle.rinet.ru> <20130609124603.GA35681@icarus.home.lan>
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On Sun, 9 Jun 2013, Jeremy Chadwick wrote: [back to second part] [and snip a lot here too] > Where someone stated that excessive ARC usage on ZFS had an indirect > effect on tmpfs. r233769 to stable/9 may have fixed this, but given the > history of all of this "juggling" of Feature X causing memory exhaustion > for Feature Y, and in turn affecting Feature Z, all within kernel space, > I really don't know how much I can trust all of this. > > One should probably review the FreeBSD forums for other posts as well, > as gut feeling says there's probably more there too. .. that's why I'm trying to discuss this in public (maybe wrong list had been chosen, perhaps -stable@ would fit a bit more) -- to share knowledge, opinions and other related stuff ;) > In closing: > > If you want to make bsdinstall ask/prompt the administrator "would you > like to use tmpfs for /tmp?", then I'm all for it -- sounds good to me. > But doing it by default would be something (at this time) I would not be > in favour of. I just don't get the impression of stability from tmpfs > given its track record. (Yes, I am paranoid in this regard) Agree at most. > *** -- For example I personally have experienced strange behaviour when > ZFS+UFS are used on the same system with massive amounts of I/O being > done between the two (my experience showed the ZFS ARC suddenly limiting > itself in a strange manner, to some abysmally small limit (much lower > than arc_max)). In this case, I can only imagine tmpfs making things > "even worse" given added memory pressure and so on. For our backup server, which uses rather huge 24*2T raidz2 and periodically synced on eSATA UFS, I sometimes seen speed drops, but nothing really bad. It's stable/9 with 16G of RAM though, perhaps on systems where RAM is tighter the situation could be much worse... -- Sincerely, D.Marck [DM5020, MCK-RIPE, DM3-RIPN] [ FreeBSD committer: marck@FreeBSD.org ] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------
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