Messages in this thread | | | Subject | Re: Mounting NFS root FS | From | Trond Myklebust <> | Date | Mon, 04 Dec 2006 13:21:30 -0500 |
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On Mon, 2006-12-04 at 19:12 +0200, Janne Karhunen wrote: > > 2) NFS provides persistent storage. > > To me this sounds like a chicken and an egg problem. It > both depends and provides this at the same time :/. But > hey, if it's supposed to work then OK.
??? Locking depends on persistent storage, but persistent storage never depended on locking. Neither rpc.statd nor lockd, nor the nfs client depend on locking working a priori.
> Anyhoo, I tried this at some stage and failed as random > clients seemed to occasionally get stuck in insmod¹ at > boot (infinite wait on lock that never gets released). > At that stage guess was that server could not properly > recognize client reboot given stale client lock data. > But if it's supposed to work I guess I have to give it > another shot and do better analysis on it. > > What about NLM/NSM protocol issues - do they properly > deal with packet loss and clients that stay down (client > holding a lock crashing and staying down; will the lock > ever be released)?
1) Packet loss is dealt with by retrying ad-infinitum.
2) No. The problem of client crashes was fixed in NFSv4 with the addition of lease-based locks.
> ¹ And why does insmod require a lock on module at load??
Does it? I've no idea why it should need that.
Trond
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