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View Full Version : WOL after a long time off ? Issue



Mnyb
2013-11-10, 00:31
This is a strange one . I don't actually expect to solve it but plausible explanations would be nice .

WOL works fine for me , with one exception if I've been away for some weeks ( work usually ).

It does not work I have to manually fire up the server once then all is fine indefinitely until next time duty drags me away to some obscure corner of the country ( or elsewhere ).

Does not work: no interface can WOL the server not any of my players not iPeng ( not even manually ) not etherwake on my desktop , not the WOL UI in my tomato flashed router .

I gues I have do more structured testing .

I * think * it does not mather if the equipment is plugged in in my abscence or not , but I could be wrong ?
I can't reproduce the issue by powering of everything and wait a reasonable time I * think * .

This is not easy to test as when it works again I have to wait to after my next work related travell .

A thing I suspect would be the NIC in the server does it need to be powered all the time ? It needs power to be able to perform WOL that part works it has some 5v running as soon as it is conected to the mains, but it would it " forget this " after prolonged power outage . I my problem is a limit to some memory capacitor in the NIC ?

DJanGo
2013-11-10, 01:20
Hi,

Wol is a complex thing.
its Hard & Softwarebased.
So please describe your Network and what Versions / Os you have (with the problems)

Basic is:
The "Bios"/UEFI has a Menü - WOL must be enabled.
The Switch/ Router has a Map "this MAC Adress" is here "this Mac Address" is there and "that MacAdress" is internal unknown.

May it helps to put Reserved Ips for your stuff - then the Router knows "that MAC Address is local".

To tell you about my office - everytime i get a new (fresh) System i cant WOL it up - even when i know the MAC. It has to be online one time.
(But i dont poweroff the switches/Router)
If a "winblows" system bluescreens and i shut it down / or i shut it down the "Hard" way - i cant wol it on.
It has to start "clean" one Time.

So ves - there is some knowledge (for working WOL) inside your Stuff that is lost when you power it off.

cheers

Mnyb
2013-11-10, 02:21
The server is HP microserver N36L with clear OS 6 beta ( redhat Linux )

WOL is enabled in bios it works for my daily and weekly use , the problem only occurs after a long time away .

The router is an old linksys wrt54L with tomato firmware there are some simple Netgear switches in use ( blue small officestuff no settings or advanced features ) .

Basically it's Internet to router , router to switches then all computers server and desktop are wired two squeezeboxes are wired.

It's one network with one subnet as simple as you can have it .

Server , computer and squeezeboxes have static network adresses outside of the routers DCHP pool .
Combined with switches that means that the desktop and the server can comunicate even when the router is down .

That's why I suspect the NIC in the server as I use "etherwake" on my desktop ( the desktop is linux mint )that basically is wired to the server and send a magic package aimed at the correct mac for th server NIC ?

Also the tomato router software has a feature where can manually input the correct mac and WOL stuff, this does not work either. After a long period away it does work now

I may try to experiment with the server if it's NIC forgots it supposed to listen for WOL after prolonged off .

I may start there pulling the power cable out of the server for a bit longer time .

Mnyb
2013-11-10, 02:26
Due to my erratic travel schedule I have no clue to exactly how long I have to be away = not using the equipment

d6jg
2013-11-10, 04:32
I'd say likely to be the router forgetting the location of the server due to inactivity. ARP tables etc

Mnyb
2013-11-10, 04:40
I'd say likely to be the router forgetting the location of the server due to inactivity. ARP tables etc

But is not wol supposed to work over broadcast ? if i use an utility where i can manually spec the mac anything on the net with that mac should wake up ?

But keep the ideas coming , I'm not in a hurry is this is not disturbing functionality in the day to day use .

DJanGo
2013-11-10, 06:53
Server , computer and squeezeboxes have static network adresses outside of the routers DCHP pool .
Combined with switches that means that the desktop and the server can comunicate even when the router is down.

That's why I suspect the NIC in the server as I use "etherwake" on my desktop ( the desktop is linux mint )that basically is wired to the server and send a magic package aimed at the correct mac for th server NIC ?
I may start there pulling the power cable out of the server for a bit longer time .

Hi,

please "try" to use additional dhcp reserved addresses also - your right Servers should have fixed / static Adresses.
it may help
But dont remove the power cable, that wont fix nothing.


But is not wol supposed to work over broadcast ? if i use an utility where i can manually spec the mac anything on the net with that mac should wake up ?
yupp - but the "bios" or "uefi" hasnt a complete Ipstack. I knew some Systems that even if the Nic is plugged to a switch and the Server / PC is plugged to the power the nics wont blink unless you start them (equal if completly to the os or just with the enter Bios key pressed)


But keep the ideas coming , I'm not in a hurry is this is not disturbing functionality in the day to day use.

as d6jg also mentioned - the arpcache should be one of the things to sort out first. And you can use the trick with the reserved ips (in the dhcp / Router) to find out if it helps or not.
To make that clear - i dont want you to enable DHCP or reserved Address in the server itself - just in the router!

epoch1970
2013-11-10, 08:48
The MAC will disappear from the ARP table after a while. But as you use the broadcast IP address this should not be an issue.

Enters power management.
For a few years now PCs which are euro-compliant are mandated to feature a power off mode ~ 1Wh. Many (all?) machines will reach this level only with the Ethernet board fully powered off. In this mode the thing is dead, no matter of WOL will wake the computer.
A bios option should be available to engage/ disable the feature on the computer.
http://en.wikipedia.org/wiki/Standby_power

Same goes for "green Ethernet" switches/routers. These will modulate the power applied to an Ethernet port according to the detected cable length, negotiated speed, and will power off ports which are not connected (or connected to a dark link, I suppose.) I believe the amount of power saved by port is minuscule; but considering a sparsely populated 16-port switch operating 24/365, I suppose the initiative makes sense.
If your router/switch is of the green Ethernet kind, you will probably find an option related to power in its management interface.
http://en.wikipedia.org/wiki/Green_Ethernet

HTH

Mnyb
2013-11-10, 10:17
Thank's again ! i will read this more carefully when i get home .

Why i wanted to pull the plug was to test if the root cause is that the server looses its memory , before investigating more complex causes . It can be that simple as everything works fine ( including wol ) when i'm around .

Mnyb
2013-11-10, 12:48
One part solved for now ( I must gather more data after a long stay from home ).

Fact I forgot to mention i use WOL to boot the server it's not ojust the standby part .

The server NIC can't remember a thing even if remove the power just a couple of seconds . So power cable must be in even if the server is "off" .

Experiment :

disconnected the router from network ( to exclude any issues there and also exclude help from recent arp cache ) desktop pc off iPeng off .

Turned off the server from the front button ( confirmed OS shutdown ) pressed "on" on my boom who happens to be conected to the same switch , the server booted up fine .

Now I briefly removed power from the server , tried to WOL again no sucess . Know I know that .

Server will now WOL as usual until next power outage .

What surprised me was that it has no memory backup for this ? , so while I'm away working on some project I migth very well have some short power outage at home who I'm unaware of . That explain some of the occasions when this won't work .
NIC is on the mobo and the mobo remembers time and other settings so it has functioning backup battery it just this setting that gets dropped . So either it is a setting I can change in the bios or more likely this settings is not stored in any fprom just volatile memory so it is this way nothing to do really . It migth even be so that the network hardware just sits on the mobo but does not really share any memory and functionality with the bios and is its own thing anyway .

And I also tested that my wired players can WOL the server without any help from the router .

induna
2013-11-10, 16:43
One part solved for now ( I must gather more data after a long stay from home ).

Fact I forgot to mention i use WOL to boot the server it's not ojust the standby part .

The server NIC can't remember a thing even if remove the power just a couple of seconds . So power cable must be in even if the server is "off" .

Experiment :

disconnected the router from network ( to exclude any issues there and also exclude help from recent arp cache ) desktop pc off iPeng off .

Turned off the server from the front button ( confirmed OS shutdown ) pressed "on" on my boom who happens to be conected to the same switch , the server booted up fine .

Now I briefly removed power from the server , tried to WOL again no sucess . Know I know that .

Server will now WOL as usual until next power outage .

What surprised me was that it has no memory backup for this ? , so while I'm away working on some project I migth very well have some short power outage at home who I'm unaware of . That explain some of the occasions when this won't work .
NIC is on the mobo and the mobo remembers time and other settings so it has functioning backup battery it just this setting that gets dropped . So either it is a setting I can change in the bios or more likely this settings is not stored in any fprom just volatile memory so it is this way nothing to do really . It migth even be so that the network hardware just sits on the mobo but does not really share any memory and functionality with the bios and is its own thing anyway .

And I also tested that my wired players can WOL the server without any help from the router .

I had the same issue with my Vortexbox. I had to edit /usr/local/sbin/network_up.sh and add the following 'echo "ethtool -s eth0 wol g" | at now + 1 minute' to set the WOL configuration after the network had started. This is with Fedora 16, so YMMV.

Mnyb
2013-11-10, 19:47
I had the same issue with my Vortexbox. I had to edit /usr/local/sbin/network_up.sh and add the following 'echo "ethtool -s eth0 wol g" | at now + 1 minute' to set the WOL configuration after the network had started. This is with Fedora 16, so YMMV.

Really ? I'll check my configuration , I have something similar already so WOL is working but it was years since I've done that .
Do your vbox handle the total loss of power case ?

induna
2013-11-10, 20:15
Really ? I'll check my configuration , I have something similar already so WOL is working but it was years since I've done that .
Do your vbox handle the total loss of power case ?

Yes, it does. I believe that the problem was a timing issue. Although the WOL setting was correct, it was being applied before the network interface loaded and wasn't taking effect after cold boots, but did take effect after warm boots. The work-around re-applies the proper configuration after the network has been up for 1 minute. You may be having a different issue, but even so this might point you in the right direction.

Mnyb
2013-11-10, 20:28
Yes, it does. I believe that the problem was a timing issue. Although the WOL setting was correct, it was being applied before the network interface loaded and wasn't taking effect after cold boots, but did take effect after warm boots. The work-around re-applies the proper configuration after the network has been up for 1 minute. You may be having a different issue, but even so this might point you in the right direction.

Interesting it could be hardware dependent too I can't remember my old server doing this .
In fact I will check even closer it was so long ago that I migth remember it wrong , my old server needed some script a long these lines to even to do a varm boot ! I'll check if my current OS and hardware really needed that .
I migth have skipped this part if WOL " just worked " or reused a solution that does not really fit this hardware .

Thanks for the input . I'm really no computer expert so I have to work a bit to get around these things .

Do you use a hardware vortexbox or are you using a microserver ? Some HP microservers are used as vorteboxes .

induna
2013-11-10, 21:23
Interesting it could be hardware dependent too I can't remember my old server doing this .
In fact I will check even closer it was so long ago that I migth remember it wrong , my old server needed some script a long these lines to even to do a varm boot ! I'll check if my current OS and hardware really needed that .
I migth have skipped this part if WOL " just worked " or reused a solution that does not really fit this hardware .

Thanks for the input . I'm really no computer expert so I have to work a bit to get around these things .

Do you use a hardware vortexbox or are you using a microserver ? Some HP microservers are used as vorteboxes .

I'm using a Zotac Box Nano. It works very well.

Mnyb
2013-11-11, 06:17
I had the same issue with my Vortexbox. I had to edit /usr/local/sbin/network_up.sh and add the following 'echo "ethtool -s eth0 wol g" | at now + 1 minute' to set the WOL configuration after the network had started. This is with Fedora 16, so YMMV.

nah that did not work i had to set it elsewhere but it it did not take ( i tried different variations to ) .

Workaround is to have the server to boot at powerfailure , possibly another NIC may actually work

epoch1970
2013-11-11, 07:29
What surprised me was that it has no memory backup for this ?
I don't think this has much to do with "memory".
I surmise either:
a - soft power off mode differs from cold power off in the network card status
b - when the machine encounters a power failure event, somehow the bios gets zapped to a factory config that has the NIC disabled in power off mode

I've seen b) happen, but typically this would require many power failures in a row (like a machine failing to boot a few times, and the bios rolling back to failsafe defaults). Or a dead battery on the motherboard (sensors should tell you that; or the date reported by the machine early in the boot process.)
For me the most probable circumstance is a) and I would try 2 things:
1 - check there isn't a bios option to keep the network card active in cold off mode.
2 - change the power failure mode to "restart", and rely on the OS power management logic to bring the machine to soft-off again after a while.

I would prefer option 1) to work, by a mile. Power events rarely come alone, it's probably better not to have the server get caught by a secondary power failure while it is checking its disk drive due to the 1st unexpected restart...

(or perhaps you can get creative with the bios scheduled start feature --like: every day at 10pm--, depending of how it behaves when the machine is in soft-off mode, and how you can manipulate this setting from the booted OS...)

Mnyb
2013-11-11, 08:18
I don't think this has much to do with "memory".
I surmise either:
a - soft power off mode differs from cold power off in the network card status
b - when the machine encounters a power failure event, somehow the bios gets zapped to a factory config that has the NIC disabled in power off mode

I've seen b) happen, but typically this would require many power failures in a row (like a machine failing to boot a few times, and the bios rolling back to failsafe defaults). Or a dead battery on the motherboard (sensors should tell you that; or the date reported by the machine early in the boot process.)
For me the most probable circumstance is a) and I would try 2 things:
1 - check there isn't a bios option to keep the network card active in cold off mode.
2 - change the power failure mode to "restart", and rely on the OS power management logic to bring the machine to soft-off again after a while.

I would prefer option 1) to work, by a mile. Power events rarely come alone, it's probably better not to have the server get caught by a secondary power failure while it is checking its disk drive due to the 1st unexpected restart...

(or perhaps you can get creative with the bios scheduled start feature --like: every day at 10pm--, depending of how it behaves when the machine is in soft-off mode, and how you can manipulate this setting from the booted OS...)

Yes I could not find such mode in the bios it's rather simplistic compared to my desktop who has all sort of stuff for everything . Cold of would mean some memory in prom or a battery there is no power so it has to remeber somehow a pity there is no bios settingto remebr this .

The power modes are on,off and "current mode" (they chose another wording that eludes me) ? the "current" selection mean that it would return to the state it was in before the power failure .
That means if it was off it would return to be off (orange lligth on the front NIC blinking ) but that apearently does not include listening for wol, packages .

I rather live with as is it's really not a big problem ,actually having multiple reboots could potentially be a bigger problem as you say .

But it satifies curiusity as why its happens , so less of a mystery most of my wol dysfunctions comes down to this , and it happens a couple of tiḿes on a year :) so it's not really worth to pursiut actively . I collect information and keep an Eye on it .

There are bois mods but not target this issue .