Date: Mon, 9 Mar 1998 03:01:33 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: dyson@FreeBSD.ORG Cc: karpen@ocean.campus.luth.se, current@FreeBSD.ORG Subject: Re: Okay, -current should be conditionally safe to use Message-ID: <199803090301.UAA15987@usr08.primenet.com> In-Reply-To: <199803080012.TAA00282@dyson.iquest.net> from "John S. Dyson" at Mar 7, 98 07:12:31 pm
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> > Would tuning the NFS exported disk SoftUpdates do a significant difference? > > > Yes. > > > For the moment I don't think we're ready to use the SoftUpdates code, since > > we're using the machine for more then just play, but it might be an > > interesting thing to try once it's more robust. > > It probably isn't a good idea to use softupdates in production yet. However, > another interesting thing to try is: > > sysctl -w vfs.nfs.async=1 > > on the server. This is better (safer) than softupdates, but you *can* > have data lossage, due to writes not being committed to disk. It is > a good idea to have a UPS when using the above option. Note: it is a technical violation of the NFS protocol specification for an NFS server to ACK a write which has not been commited to stable storage. The "Prestoserve" stuff commits the writes to stable storage (battery backed RAM). The Auspex and NetWork Appliance stuff works similarly. The vfs.nfs.async sysctl, Soft Updates, and the SunOS/Solaris/SVR4 write gathering, as well as the SVR4 Delayed Ordered Writes (DOW) are all, in a sense, technical violations. For more information, see: X/Open CAE Specification C218 Protocols for X/Open PC Interworking: XNFS, Issue 4 ISBN: 1-872630-66-9 If you are concerned about fault tolerance, then you should look into a UPS (#define NFS_SERVER STABLE_STORAGE). Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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