Happy new year From: "Simon Riggs" <[EMAIL PROTECTED]> > Have you tried setting deadline scheduler on the WAL device and CFQ on > the data device? That should allow the I/Os to move through different > queues and prevent interference.
No, I've not tried yet. Inaam-san told me that Linux had a few I/O schedulers but I'm not familiar with them. I'll find information about them (how to change the scheduler settings) and try the same test. ----- Original Message ----- From: "Simon Riggs" <[EMAIL PROTECTED]> To: "Takayuki Tsunakawa" <[EMAIL PROTECTED]> Cc: "ITAGAKI Takahiro" <[EMAIL PROTECTED]>; <pgsql-hackers@postgresql.org> Sent: Thursday, December 28, 2006 7:07 AM Subject: Re: [HACKERS] Load distributed checkpoint > On Mon, 2006-12-18 at 14:47 +0900, Takayuki Tsunakawa wrote: >> Hello, Itagaki-san, all >> >> Sorry for my long mail. I've had trouble in sending this mail because >> it's too long for pgsql-hackers to accept (I couldn't find how large >> mail is accepted.) So I'm trying to send several times. >> Please see the attachment for the content. > > Your results for fsync are interesting. > > I've noticed that a checkpoint seems to increase the activity on the WAL > drive as well as increasing I/O wait times. That doesn't correspond to > any real increase in WAL traffic I'm aware of. > > Have you tried setting deadline scheduler on the WAL device and CFQ on > the data device? That should allow the I/Os to move through different > queues and prevent interference. > > -- > Simon Riggs > EnterpriseDB http://www.enterprisedb.com > > > ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster