Re: NFS and /dev/mdXpY

[Steve Cousins <steve.cousins@maine.edu>]

Since md2 with XFS is acting fine locally, it seems to be an NFS issue. 
What export and mounting parameters are you using?


Vlad Glagolev wrote:
> Well, hello there,
>
> Posted it on linux-kernel ML also, and post it here, for more specific analysis.
>
> I faced this problem today while trying to mount some NFS share on OpenBSD box.
> I mounted it successfully without any visible errors, but I wasn't able to cd there, the printed error was:
>
> ksh: cd: /storage - Stale NFS file handle
>
> Apropos, the partition is 5.5 TB. I tried another one on my box and it was mounted successfully. It was possible to manage files there too. Its size is ~3GB.
> That's why the first time I thought about some size limitations of OpenBSD/Linux/NFS.
>
> While talking on #openbsd @ freenode, I discovered this via tcpdump on both sides:
>
> http://pastebin.ca/1864713
>
> Googling for 3 hours didn't help at all, some posts had similiar issue but either with no answer at all or without any full description.
>
> Then I started to experiment with another Linux box to kill the possible different variants.
>
> On another box I also have nfs-utils 1.1.6 and kernel 2.6.32. Mounting that big partition was unsuccessful, it got just stuck. On tcpdump I've seen this:
>
> --
>     172.17.2.5.884 > 172.17.2.2.2049: Flags [.], cksum 0x25e4 (correct), seq 1, ack 1, win 92, options [nop,nop,TS val 1808029984 ecr 1618999], length 0
>     172.17.2.5.3565791363 > 172.17.2.2.2049: 40 null
>     172.17.2.2.2049 > 172.17.2.5.884: Flags [.], cksum 0x25e6 (correct), seq 1, ack 45, win 46, options [nop,nop,TS val 1618999 ecr 1808029984], length 0
>     172.17.2.2.2049 > 172.17.2.5.3565791363: reply ok 24 null
>     172.17.2.5.884 > 172.17.2.2.2049: Flags [.], cksum 0x259b (correct), seq 45, ack 29, win 92, options [nop,nop,TS val 1808029985 ecr 1618999], length 0
>     172.17.2.5.3582568579 > 172.17.2.2.2049: 40 null
>     172.17.2.2.2049 > 172.17.2.5.3582568579: reply ok 24 null
>     172.17.2.5.3599345795 > 172.17.2.2.2049: 92 fsinfo fh Unknown/0100030005030100000800000000000000000000000000000000000000000000
>     172.17.2.2.2049 > 172.17.2.5.3599345795: reply ok 32 fsinfo ERROR: Stale NFS file handle POST:
>     172.17.2.5.3616123011 > 172.17.2.2.2049: 92 fsinfo fh Unknown/0100030005030100000800000000000000000000000000000000000000000000
>     172.17.2.2.2049 > 172.17.2.5.3616123011: reply ok 32 fsinfo ERROR: Stale NFS file handle POST:
>     172.17.2.5.884 > 172.17.2.2.2049: Flags [F.], cksum 0x2449 (correct), seq 281, ack 129, win 92, options [nop,nop,TS val 1808029986 ecr 1618999], length 0
>     172.17.2.2.2049 > 172.17.2.5.884: Flags [F.], cksum 0x2476 (correct), seq 129, ack 282, win 46, options [nop,nop,TS val 1618999 ecr 1808029986], length 0
>     172.17.2.5.884 > 172.17.2.2.2049: Flags [.], cksum 0x2448 (correct), seq 282, ack 130, win 92, options [nop,nop,TS val 1808029986 ecr 1618999], length 0
> --
>
> familiar messages, eh?
>
> Since that time I've solved that's not OpenBSD problem. So only NFS and Linux left as the reasons of this.
> It was possible to mount that small partition on Linux box too, the same as on OpenBSD.
>
> But afterthat I recongnized an interesting issue: I have different sw raid setups on my storage server.
> I tried to mount a small partition on the same md device where 5.5TB partition is located, and got the same
> error message! Now I'm sure it's about NFS <-> MDADM setup, that's why I called the topic like this.
>
> A bit about my setup:
>
> # cat /proc/mdstat 
> Personalities : [linear] [raid0] [raid1] [raid6] [raid5] [raid4] [multipath] 
> md3 : active raid1 sdc1[0] sdd1[1]
>       61376 blocks [2/2] [UU]
>       
> md1 : active raid5 sdc2[2] sdd2[3] sdb2[1] sda2[0]
>       3153408 blocks level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
>       
> md2 : active raid5 sdc3[2] sdd3[3] sdb3[1] sda3[0]
>       5857199616 blocks level 5, 512k chunk, algorithm 2 [4/4] [UUUU]
>       
> md0 : active raid1 sdb1[1] sda1[0]
>       61376 blocks [2/2] [UU]
>       
> unused devices: <none>
>
> md0, md1, and md3 aren't so interesting, since fs is created directly on them, and that's a _problem device_:
>
> # parted /dev/md2
> GNU Parted 2.2
> Using /dev/md2
> Welcome to GNU Parted! Type 'help' to view a list of commands.
> (parted) p free                                                           
> p free
> Model: Unknown (unknown)
> Disk /dev/md2: 5998GB
> Sector size (logical/physical): 512B/512B
> Partition Table: gpt
>
> Number  Start   End     Size    File system     Name   Flags
>         17.4kB  1049kB  1031kB  Free Space
>  1      1049kB  2147MB  2146MB  linux-swap(v1)  swap
>  2      2147MB  23.6GB  21.5GB  xfs             home
>  3      23.6GB  24.7GB  1074MB  xfs             temp
>  4      24.7GB  35.4GB  10.7GB  xfs             user
>  5      35.4GB  51.5GB  16.1GB  xfs             var
>  6      51.5GB  5998GB  5946GB  xfs             vault
>         5998GB  5998GB  507kB   Free Space
>
> # ls /dev/md?*
> /dev/md0  /dev/md1  /dev/md2  /dev/md2p1  /dev/md2p2  /dev/md2p3  /dev/md2p4  /dev/md2p5  /dev/md2p6  /dev/md3
>
> It's very handy partitioning scheme where I can extend (grow 5th raid) with more hdds only /vault partition while "loosing" (a.k.a. not using for this partition) only ~1gb of space from every 2TB drive.
>
> System boots ok and xfs_check passes with no problems, etc.
> The only problem: it's not possible to use NFS shares on any partition of /dev/md2 device.
>
> Finally, my question to NFS and MDADM developers: any idea?
>
>