Snapshotting and me

[drizzt81]

Hello,

so I have finally decided that it's time to get into the snapshotting business. I looked at the old thread and realize that this may be a bit of a pain, but let's see what we can do.

I am running a Win2K3 domain with a two DCs, one per site. The sites are connected via a VPN, which is really slow (say ~128kbit). Each user has a roaming profile stored on a domain DFS root that replicates between the sites. The 'my documents' folder is redirected to the same DFS root and is also replicated. I would be fine with taking daily snapshots of the "my documents", favorites etc. from either DC.

For my coding work, I have a CVS server installed on my local DC. I check out copies of the files into a "localdocs" folder on my machines. Since I am not the best about commiting changes frequently, I feel that snapshotting these directories on an hourly basis would be nice.

It would be nice if I could integrate the Linux snapshotting box into my Win2K3 domain, so that I would not have to allow 'everyone' read permissions on the shared folders that I want to snapshot.

I am considering to put the snapshot server on a Via Epia CL10000, which I have lying around here with a 200 GB Seagate HDD.

So, let's get started: what Linux distro should I install and how should I partition the HDD?

 

[unhappy_mage]

Windows domains support Kerberos, correct? I strongly believe any modern version of Linux you put on that machine will know how to AD-ify itself out of the box. See for example this walkthrough for Debian. I've never done this part, but I believe it to be relatively straightforward. Sorta.

As for the snapshotting bit: why not just have a script that commits changes every so often? CVS lets you get a copy from an arbitrary time, right? Snapshotting the MyDocs should be fairly straightforward, but with EVMS there's always a bit of putzing about with terminology to be done. I'll make a VM tonight and play with doing this in the morning.

 

[unhappy_mage]

Okay, having given up on sleep, here's my guide to snapshotting. The first thing to notice here is that each snapshot should be given the same amount of space as the original volume, so that if changes should happen to the source volume that cause all of the blocks to change there won't be a crash. I will stress test this in a minute, but for now I want my VM working

Setup portion
I'm going to assume that you've got two disks; the first with a volume that EVMS knows as "/dev/evms/source". It doesn't matter what the filesystem on this device is. Then you've got another disk with no partitions on it which you'll use to store the snapshot volumes. This second device must be at least (number of snapshots kept)*(size of snapshot volume), to prevent crashes. First we'll make a "region" with LVM to hold the set of snapshot regions. Go to the "available objects" tab (if there isn't one, you'll need to clear whatever's off the snapshot volume first). Go to Actions->create container, LVM, next, select the volume, name it "snapcont" or whatever you feel like. For each snapshot you wish to make, (I'm using the EVMS gui; the ncurses one will work in a similar way) go to the Regions tab, select "lvm/snapvol/freespace", right-click and select "create region", name it "snapregN" (where N is the snapshot number you're on), make its size as big as the snapshotted volume, click ok.

Now in the "available objects" tab you should have N available objects, all the same size. For each, right-click, "create feature object", "snapshot feature", select the source volume, name it "snapobjN", not writeable, ok. This is all the setup we need. Amazing, huh?

The script
What this is designed to do is rotate backups once an hour. Run it once and it'll rotate once.

I'm getting close with the script; it's a work in progress. But I need to wake up and go to class

 

[space_monkey]

I'm currently planning to setup a linux backup server which needs to plug into a Windows 2003 DC. Thanks for the link to the Debian-AD howto!
Looking forward to seeing the rolling backup scripts...

 

[unhappy_mage]

Sorry for the delays - I had about the worst week I've had all semester in terms of getting up at a reasonable hour (see also post times), and now I've got class all day and I'm awake to go to them, so I'm gonna do that. I'm guessing that on Friday afternoon will be the first time I get a chance to post this. Sorry about the delay.

 

[drizzt81]

a little update from my side for now:

• I have installed debian (unfortunately without the GUI) on my 'epiaserv' machine
• It authenticates users with AD. Therefore I can now log into the debian workstation as LOCALDOMAIN\Administrator with my domain password and work from there.
• I can access a user's homedir on epiaserv from my windows workstation

There are a few problems:

• in order to access a share on my DC from epiaserv logged in as a domain users, I need to supply a password
• lack of GUI makes it a bit of a pain to work with, but I am doing ok so far, EVMS seems to prefer GUI though.

 

[drizzt81]

ok, so i have KDE, Xwindows and some other stuff installed now. Found out that smb4k does not work with my configuration, after spending about 4 hours on getting the appropriate packages for linux in order to compile and install smb4k

Aaaanyway:

I got the EVMS, EVMS-GUI, EVMS-CLI and EVMS-NCURSES. Do I need kernel-patch-evms ?

This is my current setup:

epiaserv:/# di
Filesystem         Mount               Megs     Used    Avail %used fs Type
/dev/hda2          /                 6061.0    796.6   4956.4  18%  ext3
tmpfs              /dev/shm           236.3      0.0    236.3   0%  tmpfs
/dev/hda7          /home            15665.8     32.8  14837.2   5%  ext3

as you can see the number of blocks does not add up to 160GB, since I have a partition that I planned to use later for data storage. It is approx 130GB in size and neither formatted nor mounted.

Should I use EVMS to manage that partition or mount/ format it another way (if the latter, how?)

 

[unhappy_mage]

Wow, I completely forgot about this thread. I'll get on that script for yall.

WRT smb4k, try "smb://host/share" in Konqueror. Good enough?

You shouldn't need the kernel patch; your root filesystem isn't going to be on an EVMS volume (EVMS will recognize it fine, though - be sure not to delete it ).

See post #3 for setup instructions. I can post screenshots if you like, thanks to the magic of VMware.

 

[drizzt81]

I'm currently planning to setup a linux backup server which needs to plug into a Windows 2003 DC. Thanks for the link to the Debian-AD howto!
Looking forward to seeing the rolling backup scripts...

let me make a quick note here:

while configuring samba, you will notice that the author suggests that you set the following parameter in the [general] section:

winbind separator = '\'

I strongly advise against this, since it messed up my install a bit. You can just leave out this definition, since winbind uses the backslash as the default separator anyway. If you do what he suggests, you can check the winbind configuration using testparm -v and you will notice that you get an error saying that the separator has the be only one character. Since the backslash is used for linebreaking, you cannot use it in the configuration files (at least there have been a couple of people with quite some trouble when using it).

Bottom line: if you want to use the backslash, leave the option out of the smb.conf. If you want to use anything else, set the option as you desire.

 

[drizzt81]

Wow, I completely forgot about this thread. I'll get on that script for yall.

take your time, this project isn't moving all that fast anyway.

WRT smb4k, try "smb://host/share" in Konqueror. Good enough?

yeah that works, and smbclient -k //server/share also works pretty nice. I just wanted a pretty GUI.

You shouldn't need the kernel patch; your root filesystem isn't going to be on an EVMS volume (EVMS will recognize it fine, though - be sure not to delete it ).

See post #3 for setup instructions. I can post screenshots if you like, thanks to the magic of VMware.

I still need to install the second HDD before attempting this. Please note that I am 'learning linux' on the side while working on this project, so stuff takes me a lot longer than others