Mailing List Archive

Xen SR NFS mount options = soft
Dear Xen community,

We are running XenServer 6.02 and 6.1, using NFS mounts from a Nexenta ZFS
file system as our Storage Repositories.

Occasionally, the Nexenta system freezes for up to 50 to 2 minutes seconds
(no idea on that yet), which should not hurt the Xen guests as its just a
temporary freeze of an NFS share.

However, the XenServer hypervisor mounts its NFS storage repositories with
the option "soft", so the SRs just disconnect. Major mayhem ensues as the
virtual guests put their root file systems into read-only mode.

I have not figured out how to NFS mount a Xen Storage Repository on a
Xenserver with the "hard" option.

Here is what "nfsstat -m" shows for our hypervisor's NFS mount options
(note the 'soft' item on each SR)

[root@new-ucsc1b1 ~]# nfsstat -m

/var/run/sr-mount/92bf4ab7-8ce9-ed6a-a04a-e7b3c0e3348b from 10.10.15.247:
/volumes/dev0/XEN_6.1_SR/92bf4ab7-8ce9-ed6a-a04a-e7b3c0e3348b

Flags:
rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,
*soft*
,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.15.247


/var/run/sr-mount/95144379-5caf-cc1b-1861-39825b4bbe7b from 10.10.8.137:
/backup

Flags:
rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,
*soft*
,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.8.137


/var/run/sr-mount/6bcb8d28-99bd-a803-f6b0-5c43a1cdbb96 from 10.10.15.247:
/volumes/dev0/XEN_6.1_SR_hard/6bcb8d28-99bd-a803-f6b0-5c43a1cdbb96

Flags:
rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,
*soft*
,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.15.247

Does anyone know how to NFS mount a Xen Storage Repository 'hard'?

Thank you,
Kel

Kelvin Vanderlip
I.T. Systems Administration
Sunrider Torrance
*"The biggest single problem in communication is the illusion that it has
taken place"*

CONFIDENTIALITY NOTICE: This message is intended only for the use of the individual or entity to which it is addressed, and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If you have received this email in error, please immediately notify the sender by return email and delete this email and any attachments from your system.
Re: Xen SR NFS mount options = soft [ In reply to ]
Look at /opt/xensource/sm/nfs.py

The nfs mount options are hard coded in the soft_mount function. You can change the options in there.

From: xen-users-bounces@lists.xen.org [mailto:xen-users-bounces@lists.xen.org] On Behalf Of Kelvin Vanderlip
Sent: Friday, July 05, 2013 6:17 PM
To: xen-users@lists.xen.org
Subject: [Xen-users] Xen SR NFS mount options = soft

Dear Xen community,

We are running XenServer 6.02 and 6.1, using NFS mounts from a Nexenta ZFS file system as our Storage Repositories.

Occasionally, the Nexenta system freezes for up to 50 to 2 minutes seconds (no idea on that yet), which should not hurt the Xen guests as its just a temporary freeze of an NFS share.

However, the XenServer hypervisor mounts its NFS storage repositories with the option "soft", so the SRs just disconnect. Major mayhem ensues as the virtual guests put their root file systems into read-only mode.

I have not figured out how to NFS mount a Xen Storage Repository on a Xenserver with the "hard" option.

Here is what "nfsstat -m" shows for our hypervisor's NFS mount options (note the 'soft' item on each SR)

[root@new-ucsc1b1 ~]# nfsstat -m

/var/run/sr-mount/92bf4ab7-8ce9-ed6a-a04a-e7b3c0e3348b from 10.10.15.247:/volumes/dev0/XEN_6.1_SR/92bf4ab7-8ce9-ed6a-a04a-e7b3c0e3348b

Flags: rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,soft,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.15.247


/var/run/sr-mount/95144379-5caf-cc1b-1861-39825b4bbe7b from 10.10.8.137:/backup

Flags: rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,soft,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.8.137


/var/run/sr-mount/6bcb8d28-99bd-a803-f6b0-5c43a1cdbb96 from 10.10.15.247:/volumes/dev0/XEN_6.1_SR_hard/6bcb8d28-99bd-a803-f6b0-5c43a1cdbb96

Flags: rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,soft,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.15.247

Does anyone know how to NFS mount a Xen Storage Repository 'hard'?

Thank you,
Kel

Kelvin Vanderlip
I.T. Systems Administration
Sunrider Torrance
"The biggest single problem in communication is the illusion that it has taken place"

CONFIDENTIALITY NOTICE: This message is intended only for the use of the individual or entity to which it is addressed, and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If you have received this email in error, please immediately notify the sender by return email and delete this email and any attachments from your system.
Re: Xen SR NFS mount options = soft [ In reply to ]
Thank you, Joseph, you are a star. I spent quite a while trying to use the
"Advanced Options" text box in XenCenter's NFS SR dialogue without any
effect on anything. No one except you knew where those options could be
set. Its odd that NFS options are set in code, not data.

I found a discussion on NFS mount options here
http://forums.citrix.com/thread.jspa?threadID=274380&tstart=0 with a nice
analysis by Colin Hutcheson. I'll work a few test NFS crashes and let you
know how "rw,tcp,bg,hard,intr,sync,noac,rsize=32768,wsize=32768,time
o=600,retrans=2,_netdev" works for me.

With best regards,
Kel

Kelvin Vanderlip
I.T. Systems Administration
Sunrider Torrance
*"The biggest single problem in communication is the illusion that it has
taken place"*



On Mon, Jul 8, 2013 at 7:30 AM, Joseph Hom <jhom@softlayer.com> wrote:

> Look at /opt/xensource/sm/nfs.py****
>
> ** **
>
> The nfs mount options are hard coded in the soft_mount function. You can
> change the options in there.****
>
> ** **
>
> *From:* xen-users-bounces@lists.xen.org [mailto:
> xen-users-bounces@lists.xen.org] *On Behalf Of *Kelvin Vanderlip
> *Sent:* Friday, July 05, 2013 6:17 PM
> *To:* xen-users@lists.xen.org
> *Subject:* [Xen-users] Xen SR NFS mount options = soft****
>
> ** **
>
> Dear Xen community,****
>
> ** **
>
> We are running XenServer 6.02 and 6.1, using NFS mounts from a Nexenta ZFS
> file system as our Storage Repositories.****
>
> ** **
>
> Occasionally, the Nexenta system freezes for up to 50 to 2 minutes seconds
> (no idea on that yet), which should not hurt the Xen guests as its just a
> temporary freeze of an NFS share.****
>
> ** **
>
> However, the XenServer hypervisor mounts its NFS storage repositories with
> the option "soft", so the SRs just disconnect. Major mayhem ensues as the
> virtual guests put their root file systems into read-only mode.****
>
> ** **
>
> I have not figured out how to NFS mount a Xen Storage Repository on a
> Xenserver with the "hard" option.****
>
> ** **
>
> Here is what "nfsstat -m" shows for our hypervisor's NFS mount options
> (note the 'soft' item on each SR)****
>
> ** **
>
> [root@new-ucsc1b1 ~]# nfsstat -m****
>
> ** **
>
> /var/run/sr-mount/92bf4ab7-8ce9-ed6a-a04a-e7b3c0e3348b from 10.10.15.247:
> /volumes/dev0/XEN_6.1_SR/92bf4ab7-8ce9-ed6a-a04a-e7b3c0e3348b****
>
> ** **
>
> Flags:
> rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,
> *soft*
> ,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.15.247
> ****
>
> ** **
>
> ** **
>
> /var/run/sr-mount/95144379-5caf-cc1b-1861-39825b4bbe7b from 10.10.8.137:
> /backup****
>
> ** **
>
> Flags:
> rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,
> *soft*
> ,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.8.137
> ****
>
> ** **
>
> ** **
>
> /var/run/sr-mount/6bcb8d28-99bd-a803-f6b0-5c43a1cdbb96 from 10.10.15.247:
> /volumes/dev0/XEN_6.1_SR_hard/6bcb8d28-99bd-a803-f6b0-5c43a1cdbb96****
>
> ** **
>
> Flags:
> rw,sync,relatime,vers=3,rsize=131072,wsize=131072,namlen=255,acregmin=0,acregmax=0,acdirmin=0,acdirmax=0,
> *soft*
> ,noac,proto=tcp,port=65535,timeo=133,retrans=0,sec=sys,mountport=65535,local_lock=none,addr=10.10.15.247
> ****
>
> ** **
>
> Does anyone know how to NFS mount a Xen Storage Repository 'hard'?****
>
> ** **
>
> Thank you,****
>
> Kel****
>
>
> ****
>
> Kelvin Vanderlip
> I.T. Systems Administration
> Sunrider Torrance
> *"The biggest single problem in communication is the illusion that it has
> taken place"*****
>
> CONFIDENTIALITY NOTICE: This message is intended only for the use of the individual or entity to which it is addressed, and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If you have received this email in error, please immediately notify the sender by return email and delete this email and any attachments from your system.****
>
> ** **
>
>

CONFIDENTIALITY NOTICE: This message is intended only for the use of the individual or entity to which it is addressed, and may contain information that is privileged, confidential, and exempt from disclosure under applicable law. If you have received this email in error, please immediately notify the sender by return email and delete this email and any attachments from your system.
Re: Xen SR NFS mount options = soft [ In reply to ]
Hi Kelvin,

Re: http://markmail.org/thread/7kmsum42sdeswvss

How did your NFS driver changes work out for you? Did it stop the guests
remounting read-only during the 50s-2m periods of NFS unavailability?
Thanks!

--
Andrew Regan
Re: Xen SR NFS mount options = soft [ In reply to ]
Hi.
I have changed the settings on some of my systems to 'hard', and VM
reliability has increased, especially during storage failover events.

And about the Nexenta timeouts - it could be related to over-used zil
device.

Etzion
On Dec 18, 2013 12:58 PM, "Andy Regan" <andrewjregan@gmail.com> wrote:

> Hi Kelvin,
>
> Re: http://markmail.org/thread/7kmsum42sdeswvss
>
> How did your NFS driver changes work out for you? Did it stop the guests
> remounting read-only during the 50s-2m periods of NFS unavailability?
> Thanks!
>
> --
> Andrew Regan
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xen.org
> http://lists.xen.org/xen-users
>