10.8 Netboot - shadow files huge - help

[CasperSally]

A week or 2 ago I added a 10.8 Netboot to our imaging options. Today, I realized one of our servers was out of space. Looks like the shadow files created from the 10.8 Netboot set are huge - over 1.5 gigs each. With our 10.7x Netboots, shadow files were under 200MB.

Any suggestions?

I used the following 2 articles to set up 10.8.2 Netboot. Otherwise, imaging is working as expected

Creating NetBoot Images for Use with the Casper Suite
https://jamfnation.jamfsoftware.com/article.html?id=307

NetBoot Error: Startup Disk is Almost Full
https://jamfnation.jamfsoftware.com/article.html?id=198 (I did 15 gig)

Any help greatly appreciated.

[jhalvorson]

When you do netboot a system, open a Finder window, then Get Info on the netboot disk. How much available space is shown? Also, have you noticed if the more RAM installed in a system the larger the shadow file?

I am trying to learn more about the behavior of OS version, RAM amount, and proper amount to expand the netboot images too.

[CasperSally]

Capacity 16 gig and 5.89 available. Most of our machines are 2 gigs of RAM so not easy to compare.

[SeanA]

What is the size of your NetBoot.nbi ?

[CasperSally]

/private/var/vm is blank. I think that's something Composer 8.62 clears now when building OS image.

netboot.nbi is 16 gigs, but that's after I did the expand on it. Previously it was under 5 gigs. This is my 2nd attempt at a 10.8 Netboot, the first one was slow for techs and that's why I did the expand to 15 gigs.

[CasperSally]

found a macbook pro with 4 gigs of RAM. Watched the shadow file on the server, it was ~150MB until right at the end and then as machine rebooted the shadow file jumped to 1.68gig.

[tlarkin]

CasperSally,

Do you have the diskless option checked in the Netboot service?

Thanks,
Tom

[CasperSally]

Yes diskless is checked and compiled configs are coming down block copy, so diskless appears to be working properly.

[tlarkin]

On the server do you have multiple volumes? Could you perhaps put the NetbootSP0 folder on a volume that has way more free space?

Thanks,
Tom

[CasperSally]

Nope. We have one other volume that stores our packages/compiled images, but time of year when I'm testing packages for next year I need that space available.

We have thousands of Macs across 4 netboot servers. Having shadow files for each one 1-2 gigs isn't liveable unless someone is babysitting those servers.

I assume this isn't normal behaviour, the swap file being 100-200MB and then when machine reboots it jumps to 1-2GB?

[tlarkin]

Hi CasperSally,

It is hard to say what is normal. These shadow files are used so the netbooted client can write specific data to them and retrieve it after imaging time. Are you erasing the volume when you image and laying down a compiled image for block copy, at least that is what it sounds like?

How many things are configured in your imaging work flow, that could possibly need to write to a shadow file?

thanks,
Tom

[CasperSally]

Yes we erase a volume and put down a compiled or not compiled image (we have dozens of configs).

We're not doing anything differently than what we did with our 10.7 netboot set. So the shadow files should be similar size then I'd assume? They are 10x as big for 10.8 netboots (no large file increase on reboot on the 10.7 netboot).

[Kumarasinghe · Accepted solution]

Please make your 10.8 NetBoot set to use local RAM disk for shadow files;
http://www.macos.utah.edu/documentation/administration/setup_netboot_service_on_mac_os_x_10.6.x_clie...

We use this with our 10.8.1 NetBoot sets and works really well.

You can use the rc.netboot file from that site BUT need to modify these lines for OS X 10.8 NetBoot sets.
Line 168, 169
From:

kextutil -v 0 /System/Library/Filesystems/AppleShare/asp_tcp.kext
      kextutil -v 0 /System/Library/Filesystems/AppleShare/afpfs.kext

To:

kextload -v 0 /System/Library/Filesystems/AppleShare/asp_tcp.kext
          kextload -v 0 /System/Library/Filesystems/AppleShare/afpfs.kext

[CasperSally]

thanks for the suggestion Kumarasinghe but no joy. Macbook air shadow copy was 70MB. As soon as the machine rebooted, it jumped up to 1.4 gigs.

[CasperSally]

I just realized I had a typo in the edits on the netboot.rc file. First test seems to have worked, will continue to test and report back. Thanks again for posting this site, I had seen it before but hadn't needed it with 10.7 so forgot about it.