Message-Id: <24765.322937@fatcity.com> From: "Brooks, Russ" Date: Mon, 24 Mar 2003 16:08:49 -0500 Subject: UNIX fstab settings and prealloc command This is a multi-part message in MIME format. ------_=_NextPart_001_01C2F249.90D4BA30 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi, We're running online JFS on HP. We had a recommendation given to us = to replace the settings in fstab for the online redo logs and archive = logs. The settings were: =20 /dev/vgPRD03/lvPRDsaparch /oracle/PRD/saparch vxfs delaylog 0 = =20 /dev/vgPRD02/lvPRDoriglogB /oracle/PRD/origlogB vxfs delaylog 0 = =20 /dev/vgPRD01/lvPRDoriglogA /oracle/PRD/origlogA vxfs delaylog 0 = =20 /dev/vgPRD01/lvPRDmirrlogB /oracle/PRD/mirrlogB vxfs delaylog 0 = =20 /dev/vgPRD02/lvPRDmirrlogA /oracle/PRD/mirrlogA vxfs delaylog 0 =20 The recommended change would be: =20 /dev/vgPRD03/lvPRDsaparch /oracle/PRD/saparch vxfs = nodatainlog,convosync=3Ddirect 0 =20 /dev/vgPRD02/lvPRDoriglogB /oracle/PRD/origlogB vxfs = nodatainlog,convosync=3Ddirect 0 =20 /dev/vgPRD01/lvPRDoriglogA /oracle/PRD/origlogA vxfs = nodatainlog,convosync=3Ddirect 0 =20 /dev/vgPRD01/lvPRDmirrlogB /oracle/PRD/mirrlogB vxfs = nodatainlog,convosync=3Ddirect 0 =20 /dev/vgPRD02/lvPRDmirrlogA /oracle/PRD/mirrlogA vxfs = nodatainlog,convosync=3Ddirect 0 =20 =20 What a different branch of the consultants gave us was: =20 /oracle/DV1/origlogA vxfs delaylog,convosync=3Ddirect 0 2 /oracle/DV1/origlogB vxfs delaylog,convosync=3Ddirect 0 2 /oracle/DV1/mirrlogA vxfs delaylog,convosync=3Ddirect 0 2 /oracle/DV1/mirrlogB vxfs delaylog,convosync=3Ddirect 0 2 =20 They based this on a quick test using the following command: =20 /bin/time -p prealloc myfile 1000000000 =20 which indicated a slight negative impact to I/O with the nodatainlog. = I've read the man pages on prealloc, but it isn't clear that this is a = valid simulation of the online redo logs. Does anyone have experience = with this? Was this a valid test? =20 Best regards, Russ Brooks =20 ------_=_NextPart_001_01C2F249.90D4BA30 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hi,

= We're running=20 online JFS on HP. We had a recommendation given to us to replace = the=20 settings in fstab for the online redo logs and archive logs. The = settings=20 were:

/dev/vgPRD03/lvPRDsaparch    =20 /oracle/PRD/saparch    vxfs delaylog  =20 0       =20
/dev/vgPRD02/lvPRDoriglogB   =20 /oracle/PRD/origlogB   vxfs delaylog  =20 0       =20
/dev/vgPRD01/lvPRDoriglogA   =20 /oracle/PRD/origlogA   vxfs delaylog  =20 0       =20
/dev/vgPRD01/lvPRDmirrlogB   =20 /oracle/PRD/mirrlogB   vxfs delaylog  =20 0       =20
/dev/vgPRD02/lvPRDmirrlogA   =20 /oracle/PRD/mirrlogA   vxfs delaylog  =20 0

The = recommended=20 change would be:

/dev/vgPRD03/lvPRDsaparch    =20 /oracle/PRD/saparch    vxfs =20 nodatainlog,convosync=3Ddirect  =20 0       =20
/dev/vgPRD02/lvPRDoriglogB   =20 /oracle/PRD/origlogB   vxfs =20 nodatainlog,convosync=3Ddirect  =20 0       =20
/dev/vgPRD01/lvPRDoriglogA   =20 /oracle/PRD/origlogA   vxfs =20 nodatainlog,convosync=3Ddirect  =20 0       =20
/dev/vgPRD01/lvPRDmirrlogB   =20 /oracle/PRD/mirrlogB   vxfs =20 nodatainlog,convosync=3Ddirect  =20 0       =20
/dev/vgPRD02/lvPRDmirrlogA   =20 /oracle/PRD/mirrlogA   vxfs =20 nodatainlog,convosync=3Ddirect  =20 0

What a = different=20 branch of the consultants gave us was:

/oracle/DV1/origlogA vxfs delaylog,convosync=3Ddirect 0=20 2
/oracle/DV1/origlogB vxfs delaylog,convosync=3Ddirect 0=20 2
/oracle/DV1/mirrlogA vxfs delaylog,convosync=3Ddirect 0=20 2
/oracle/DV1/mirrlogB vxfs delaylog,convosync=3Ddirect 0=20 2

They = based this on a=20 quick test using the following command:

/bin/time -p prealloc myfile = 1000000000

which=20 indicated a slight negative impact to I/O with the nodatainlog. = I've read=20 the man pages on prealloc, but it isn't clear that this is a valid = simulation of=20 the online redo logs. Does anyone have experience with this? = Was=20 this a valid test?

Best=20 regards,