Date: Wed, 09 Jan 2013 14:09:46 +0900 (JST) From: Hiroki Sato <hrs@FreeBSD.org> To: jwd@FreeBSD.org Cc: freebsd-fs@FreeBSD.org Subject: Re: rc.d script for memory based zfs intent log Message-ID: <20130109.140946.1818513049591807609.hrs@allbsd.org> In-Reply-To: <20130109031834.GA14386@FreeBSD.org> References: <20130109023327.GA1888@FreeBSD.org> <20130109.115240.1198411557684741197.hrs@allbsd.org> <20130109031834.GA14386@FreeBSD.org>
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----Security_Multipart(Wed_Jan__9_14_09_46_2013_178)-- Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit John <jwd@FreeBSD.ORG> wrote in <20130109031834.GA14386@FreeBSD.org>: jw> ----- Hiroki Sato's Original Message ----- jw> > John <jwd@freebsd.org> wrote jw> > in <20130109023327.GA1888@FreeBSD.org>: jw> > jw> > jw> Hi Folks, jw> > jw> jw> > jw> Here's an rc.d script that provides a nice performance boost on jw> > jw> ZFS/NFS based file servers. It also helps in other areas not specific jw> > jw> to NFS. jw> > jw> jw> > jw> It attaches the log device at system startup and removes it at jw> > jw> system shutdown time. Example; jw> > jw> jw> > jw> memzil_pools="tank" jw> > jw> memzil_bootfs="YES" jw> > jw> service memzil onestart jw> > jw> zpool status tank jw> > jw> service memzil onestop jw> > jw> jw> > jw> This configuration provides a nice performance boost especially to jw> > jw> NFS, but also helps in other areas not specific to NFS. jw> > jw> jw> > jw> Please DO NOT USE this script if your system is not UPS backed, preferably jw> > jw> with dual power supplies on separate circuits. If your system crashes you jw> > jw> may lose data. The script contains information on recovery. jw> > jw> jw> > jw> http://people.freebsd.org/~jwd/memzil.txt jw> > jw> jw> > jw> Comments/Improvements appreciated. jw> > jw> > Why is simply setting sync=disabled to the ZFS dataset not enough? jw> jw> As you refer to, my understanding is that sync=disabled is at the dataset jw> layer. The zil approach is at the zpool layer - sync=disabled would be jw> nice at the zpool layer. Can you elaborate why it matters? If one wants to disable ZIL, just setting sync=disabled should be enough. Using memory disk to effectively disable ZIL on physical HDDs looks a roundabout way to do the same thing to me. -- Hiroki ----Security_Multipart(Wed_Jan__9_14_09_46_2013_178)-- Content-Type: application/pgp-signature Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (FreeBSD) iEYEABECAAYFAlDs+5oACgkQTyzT2CeTzy2KIgCdFLIlCEFI9Bfz0CegX4BCEst7 FwEAnjgrEkumnADWyLUIa1xr29vN3C8g =1Ic7 -----END PGP SIGNATURE----- ----Security_Multipart(Wed_Jan__9_14_09_46_2013_178)----
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