Date: Mon, 3 Oct 2011 11:37:18 -0700 From: Xin LI <delphij@gmail.com> To: Ivan Voras <ivoras@freebsd.org> Cc: freebsd-fs@freebsd.org Subject: Re: is TMPFS still highly experimental? Message-ID: <CAGMYy3tbMWU6JU1%2B%2B5XmzjZTrV1=oAgRaaDE3-=MMT73F_ojQQ@mail.gmail.com> In-Reply-To: <j6aorc$hf0$1@dough.gmane.org> References: <CAOfDtXMm9K_fbOmvG2gvXxDfKakkgpPt9MLifqDxa4wCibMExg@mail.gmail.com> <alpine.GSO.1.10.1110011122030.882@multics.mit.edu> <CADLo83-s_3H8PbbxOPPxbe0m10U0U5JW-feB294dFs%2BQ3iTWvg@mail.gmail.com> <CAGMYy3ssi%2BkAuufDTHA1z6u7jRrZwRRkCCkcO94GHNGF9Rku_w@mail.gmail.com> <20111002020231.GA70864@icarus.home.lan> <CAGMYy3sCCxOiVqeP4PVbvxnpcyoyQZoL%2Bw3nY8STYnpUNfj6JQ@mail.gmail.com> <j6aorc$hf0$1@dough.gmane.org>
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On Sun, Oct 2, 2011 at 3:33 PM, Ivan Voras <ivoras@freebsd.org> wrote: > On 02/10/2011 07:27, Xin LI wrote: > >> The problem Ivan have asserted was not confirmed by anyone who have >> swap configured properly. =C2=A0Gleb have pointed out that it might be >> related to a series of integer overflow by the way (he have also fixed >> a lot of tmpfs issues by the way). > > Well, instead of guessing I can point you to the way I got the original > situation - you said you have ZFS configured so it would be easy for you > to check. > > You should to something like this: > > =C2=A0 =C2=A0 =C2=A0 =C2=A0- configure your system to the best of your ab= ilities (but post what > you did different from the defaults) It's mostly "normal" configuration -- 6GB RAM, 14GB swap, ZFS as /usr; The following sysctl tweaks were done to make postgresql start (these are not scientific, just large enough to make it work): kern.ipc.shmmax=3D4294967296 kern.ipc.shmall=3D1048576 > =C2=A0 =C2=A0 =C2=A0 =C2=A0- install postgresql (8.4+, but I don't think = the version is > important), configure it so it gets half the system memory or 2/3 the > system memory for its shared_buffers. Configured to half of system memory (3072MB). # ipcs -a Message Queues: T ID KEY MODE OWNER GROUP CREATOR CGROUP CBYTES QNUM QBYTES LSPID LRPID STIME RTIME CTIME Shared Memory: T ID KEY MODE OWNER GROUP CREATOR CGROUP NATTCH SEGSZ CPID LPID ATIME DTIME CTIME m 65536 5432001 --rw------- pgsql pgsql pgsql pgsql 6 3295936512 2130 2130 10:57:12 11:09:17 10:57:12 Semaphores: T ID KEY MODE OWNER GROUP CREATOR CGROUP NSEMS OTIME CTIME s 65536 5432001 --rw------- pgsql pgsql pgsql pgsql 17 11:09:25 10:57:12 s 65537 5432002 --rw------- pgsql pgsql pgsql pgsql 17 10:57:12 10:57:12 > =C2=A0 =C2=A0 =C2=A0 =C2=A0- install pgbench Done. > =C2=A0 =C2=A0 =C2=A0 =C2=A0- initialize pgbench so that the database defi= nitely is larger than the > entire memory you got (NOTE: THIS IS NOT A CONTRIVED TEST - lots of > databases in practice are larger than the RAM in the server). Initialized with pgbench -i -s 500 pgbench. > =C2=A0 =C2=A0 =C2=A0 =C2=A0- run pgbench & observe the results. pgbench -t 20000 -c 64 -S pgbench Can't seem to reproduce: # df -Httmpfs Filesystem Size Used Avail Capacity Mounted on tmpfs 10G 69k 10G 0% /tmp Any suggestions? > This should create really bad contention problem for memory between > postgresql and ZFS, which should manifest itself in tmpfs shrinking to 0 > bytes free. > > If you don't get this problem then great, it might be solved! > > > (for more info on pgbench, see this: > http://www.westnet.com/~gsmith/content/postgresql/pgbench-scaling.htm). > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > --=20 Xin LI <delphij@delphij.net> https://www.delphij.net/ FreeBSD - The Power to Serve! Live free or die
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