"Merlin Moncure" <mmoncure@gmail.com> writes: > there are a few things that I can think of that can can cause postgres > to cause i/o on a drive other than the data drive: > * logging (eliminate this by moving logs temporarily) > * swapping (swap is high and changing, other ways) > * dumps, copy statement (check cron) > * procedures, especially the external ones (perl, etc) that write to disk > my seat-of-the-pants guess is that you are looking at swap. vmstat would confirm or disprove that particular guess, since it tracks swap I/O separately. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster

Ow Mun Heng <Ow.Mun.Heng@wdc.com> writes: >> vmstat would confirm or disprove that particular guess, since it tracks >> swap I/O separately. > procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu------ > r b swpd free buff cache si so bi bo in cs us sy id wa st > 2 6 300132 5684 4324 315888 420 32 1024 644 1309 485 35 11 0 54 0 > 0 6 299820 6768 4328 313004 588 76 3048 576 1263 588 36 12 0 52 0 > 0 6 299428 5424 4340 313700 480 36 2376 104 1291 438 24 9 0 67 0 > 2 6 298836 5108 4268 313788 800 0 2312 216 1428 625 30 10 0 60 0 > 2 6 298316 5692 4192 313044 876 0 1652 1608 1488 656 33 11 0 56 0 > 2 6 298004 6256 4140 312184 560 4 1740 1572 1445 601 42 11 0 47 0 > I kept looking at the io columns and didn't even think of the swap > partition. It's true that it's moving quite erratically but I won't say > that it's really thrashing. Hmmm ... my experience is that the si/so columns should show *zero* under normal load. What you're showing here is swap as a sizable percentage of total I/O load, and with the CPU spending the majority of its time in I/O wait, that's clearly where you need to focus your attention. > (YEP, I know I'm RAM starved on this machine) Yeah, that's what it looks like. Head down to your local CompUSA and get some RAM at fire-sale prices ... regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org/