[Xymon] [External] Memory leak in Windows Virtual Disk service caused by Xymon Windows Powershell client

[SebA]

Hi Zak,

Yes, I agree, a setting in a config file to enable or disable these checks
would probably be best.  Thanks for the additional information.

Kind regards,

SebA


On 16 April 2018 at 10:52, Beck, Zak <zak.beck at accenture.com> wrote:

> Hi Seb
>
>
>
> Thanks for confirming, that’s good news – I was fearing it may be the core
> disk utilisation functions which would be a much larger headache!
>
>
>
> > Is the XymonDiskPart information used for anything?  I mean, can it be
> used for anything without writing plug-ins?
>
>
>
> The [diskpart] section is used in one of our datacentres where they use
> clustering and the information is used primarily for reporting. So no, it
> is not used for anything by default.
>
>
>
> I think the best solution here is for me to add a setting in
> xymonclient_config.xml allowing you to turn off the diskpart function for
> specific servers. You can then remove your comment and continue to use
> future updates.
>
>
>
> Zak
>
>
>
> *From:* SebA [mailto:spah at syntec.co.uk]
> *Sent:* Friday, 30 March 2018 14:04
> *To:* Beck, Zak <zak.beck at accenture.com>
> *Cc:* Xymon Mailing List <xymon at xymon.com>
> *Subject:* Re: [External] Memory leak in Windows Virtual Disk service
> caused by Xymon Windows Powershell client
>
>
>
> Hi Zak,
>
> Thanks for your swift reply and sorry for my own delay!  It's good to know
> you have such extensive use of the PS client without this issue.
>
> I think you are probably right.  These issue has only appeared on servers
> using Windows Cluster Failover, where various iSCSI disks are clustered.
>
> For the record, my workaround of disabling the Virtual Disk Service caused
> no bad effects on the server, but it does prevent diskpart from running.  I
> set the service back to Manual, and it started as soon as I ran diskpart
> from an elevated Command Prompt.  Exiting diskpart causes the VDS service
> and proces to stop.
>
> When the Virtual Disk Service was set to manual, and started just by me
> running diskpart.exe, the client output has:
>
> [diskpart]
>
> diskpart:::Clustered Unknown
>
> When the service is disabled, the output is just an empty section:
>
> [diskpart]
>
> When VDS is started by me restarting the XymonPSclient service and it
> being on manual, the output is e.g.:
>
> [diskpart]
>
> diskpart:Disk 0:278 GB:Not Clustered
>
> diskpart:Disk 1:1024 MB:Clustered Active
>
> diskpart:Disk 2:25 GB:Clustered Active
>
> diskpart:Disk 3:500 GB:Clustered Active
>
> diskpart:Disk 4:300 GB:Clustered Inactive
>
> diskpart:Disk 5:1024 MB:Clustered Inactive
>
> diskpart:Disk 6:500 GB:Clustered Inactive
>
> diskpart:Disk 7:200 GB:Clustered Inactive
>
> diskpart:Disk 8:1024 MB:Clustered Inactive
>
> diskpart:Disk 9:1024 MB:Clustered Inactive
>
> diskpart:Disk 10:200 GB:Clustered Inactive
>
> diskpart:Disk 11:200 GB:Clustered Inactive
>
> diskpart:Disk 12:500 GB:Clustered Active
>
> diskpart:Disk 13:5120 MB:Clustered Active
>
> diskpart:Disk 14:500 GB:Clustered Inactive
>
> Compared with VDS running because of me running diskpart and running:
>
> “list disk”
>
> For each disk returned, “select disk {n}” and then “detail disk”
>
>
>
> for each disk (which does not leak memory) vds.exe uses about an extra MB
> of RAM when running due to the PS client.
>
> I have also now commented out the line you suggest (' $script:diskpartData
> = XymonDiskPart ') and now when I restart the XymonPSclient service with
> VDS set to Manual it does not get restarted and left running (or restarted
> at all).  So this looks like a better workaround than just disabling the
> service, but I will need to continue to monitor that.
>
> Is the XymonDiskPart information used for anything?  I mean, can it be
> used for anything without writing plug-ins?
>
>
>
> We do not have memory leaks in powershell.exe on these servers (although I
> think I may have seen it on another server), so the issue above is not
> related to Alessandro's issue.
>
> Thanks again for your help Zak, and I hope this knowledge is of benefit to
> you or others too.
>
>
>
>
> Kind regards,
>
> SebA
>
>
>
> On 14 March 2018 at 09:21, Beck, Zak <zak.beck at accenture.com> wrote:
>
> Hi Seb
>
>
>
> I’ve got hundreds of VMs running the Powershell client on Windows Server
> 2008R2, 2012R2 and 2016 and I don’t see this issue. I just checked a couple
> of servers, vds.exe is between 2MB and 20MB and around 21 threads. Same
> version of vds.exe too.
>
>
>
> I’m wondering if function XymonDiskPart has something to do with it. This
> only runs on slow scans (every 6 hours-ish by default). This runs
> ‘diskpart’ and then
>
>
>
> “list disk”
>
> For each disk returned, “select disk {n}” and then “detail disk”
>
>
>
> Maybe you could try this from the command prompt on a server with vds
> stopped and see if it restarts it. You could also try commenting out this
> line (3875, towards the end) in the client and see what happens (insert a #
> at the beginning of the line):
>
>
>
>         $script:diskpartData = XymonDiskPart
>
>
>
>
>
> Alternatively, it could be the disk utilisation code which is using
> Windows API calls in kernel32.dll – FindFirstVolume, FindNextVolume,
> FindVolumeClose, GetVolumeInformation, GetVolumePathNamesForVolumeNameW,
> GetDiskFreeSpaceEx and GetDriveType. The MSDN documentation for these
> doesn’t mention the Virtual Disk Service but I guess they could be using it.
>
>
>
> Zak
>
>
>
> *From:* SebA [mailto:spah at syntec.co.uk]
> *Sent:* Tuesday, 13 March 2018 18:14
> *To:* Beck, Zak <zak.beck at accenture.com>; Xymon Mailing List <
> xymon at xymon.com>
> *Subject:* [External] Memory leak in Windows Virtual Disk service caused
> by Xymon Windows Powershell client
>
>
>
> I have noticed a memory and thread leak in the Windows Virtual Disk
> service - or vds.exe from the process list.  This service is set to Manual
> by default and gets started when starting the XymonPSClient service on
> Windows 2008 R2.  It starts off using 32 threads, but grows forever, the
> virtual memory and physical memory (which starts under 6 MB) used slowly
> grow too.
>
> Has anyone noticed this problem and do they have a solution to it?
>
> On Windows Server 2012, the Virtual Disk service does not get started by
> Xymon Windows Powershell client, so it's obviously not started directly by
> the client, but by a request for information.  I looked into known memory
> leaks for vds.exe and the one I found was not applicable to 2008 R2, only
> 2008 and Vista.  The version of vds.exe we have is later than the version
> with the fix: 6.1.7601.17514 from 2010.
>
> The quick workaround is simply to stop the Virtual Disk Service - but as
> soon as the PSclient has used it, it does not stop properly and terminates
> unexpectedly, so one needs to set it not to restart on crash, or stop it
> immediately after starting, or to Disabled.  But it would be good to know
> why it is starting, not stopping, and leaking threads / memory!
>
>
> Kind regards,
>
> SebA
>
>
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