Anirudha Patil's BLOG: October 2012

Hello Folks,

Continuing with the previous discussion on Openfiler volume management, here we would see how to create snapshots and access it. Now snapshots is nothing but backup of the existing exported volume which would be available in case the mounted volume gets deleted, corrupted or unavailable due to other reasons.

1. First we would fill up the existing exported volume with some junk binaries or data
After some data is written over the disk we can proceed with the snapshot creation.

2. Next we navigate to the Volume which needs to be backed up or snapshot to be taken.

3. Click on Create under Snapshots section which would bring us to snapshot management. Currently since its a new volume and no snapshots are been created, list of existing snapshot volume would be empty.
Also you could schedule a automatic creation of snapshots depending on hours and latest how many to keep.
We would navigate to the last section which deals which the manual snapshot creation.
Kindly make sure, there must be free space in the volume group prior to creation of snapshot.

Here we would create a snapshot
Name : First_snapshot
Size : 300MB [We have created a partition of 500 MB on exported volume]
Share Contents : Yes [Should the snapshot be readily available for mounting after creation]

4. After creation of new snapshot the volume utilization changes and this can be verified by checking the Manage Volume again
Navigate to Volumes-->Manage Volumes

Click Manage and under List of existing snapshot volume, you can see the newly created snapshot. Click Save

5. After creation of snapshot we need to make either a existing LUN for create a new LUN
We would create a new LUN to differentiate the existing volume disks
Navigate to Volumes-->iSCSI Targets

Add a new iSCSI target value as : iqn.2006-01.snapshot
Next select the new target from drop-down list of Select a iSCSI Target
and click Change

Next go to LUN Mapping and map the new volume : /dev/iscsi/of.snapshot.iscsi_volume.first_snapshot [In my case, your might differ] to this new target

Next under Network ACL, select the appropriate share
In my case we would provide the share to ACL: Anirudha. Select Allow and Click Update

6. Now to access the new LUN, follow the similar procedure as show in previous article using Microsoft iSCSI initiator.

Navigate to Start==>Control Panel
Under Administrative Tools, you can find the iSCSI initiator
Click on it

7. Now to access the new LUN, go to Start==>Run==>diskmgmt.msc
This would launch the Disk Management MMC. Here you could see a new disk [Disk2] in offline mode.
Right click Disk2 and bring it Online

This was mounted a H: drive on my machine. When checked the contents of this drive, following were the contents

Which are same contents as that of the existing exported volume [F: drive]

This concludes the post on snapshot creation and access it. You can try creating an additional new snapshot after altering the existing exported volume [F: drive here] and mount it.
I tried it with an additional one package been added to F: drive, Please find the drive contents for all 3 of them
1. Existing exported volume - F: drive
2. First snapshot volume - H: drive
3. Second snapshot volume - I: drive

Next article preferably would be to create volumes, snapshots and access it on Linux server.

Thanks
Anirudha

Today, I'm going to post about the How-To to add new disks, create partition on them, create volume groups, and create logical volumes. Also how to map them in LUN [More about it] and access them [right now used the Windows ISCSI initiator]

From the previous article [Here] I have briefed about the installation procedure for Openfiler on virtual machine.

1. First we would need to add new disks to virtual machine.
Click the VM
Right click and go to Edit Setting
Click on Add ==>Click on Disk==> Click Next
Enter Disk Size=1GB, Click Next==>Finish
Please find the screenshot for adding the new disk to existing machine. The procedure may differ depending on the virtualization application like VirtualBox, VMware ESX etc.

2. Continue with the steps and add new disk of 1GB to existing machine. Thus the virtual disks /dev/sdb and /dev/sdc was added.

3. Now currently there are no volume groups available on the server.

4. After the disks are detected we would need to create partitions on it.

[Now the partition type can be Physical Volume or RAID volumes. We are using PV in this case]

For this navigate to Volumes-->Block Devices

Click on /dev/sdb

Navigate to bottom on page, Under Create a partition section

Mode : Primary

Partition Type : Physical Volume

Click on Create

Thus resembling the partition details as show below

5. Proceed with the same procedure on another disk /dev/sdc. Thus resembling the similar partition details as show below

6. Thus we have now created two Physical Volumes [PV] on two disks [namely sdb and sdc].

7. Next after the creation of PV's we should bind them together in a Volume Group [VG].

Navigate to Volumes-->Volume Groups

Under Volume Group Management, we are able to see the newly created PV's.

Name: ISCSI

Selected both the check-box for physical volumes to add

Click on Add volume group

Thus a new VG would be created which is similar to above screen. You may see the PV associated with it by Clicking View member PVs or could delete it using Delete

8. After creation of PV's and VG we are now in position to create Logical Volumes [LV] on them.

Navigate to Volume-->Add Volume

Under “Create a volume” section

Name : iscsi_volume

Volume Description : Volume for ISCSI

Required Space (MB) : 1024 [i.e. 1GB]

Filesystem / Volume type : iSCSI

The same can be verified by checking the Volume Groups again. This time a new VG and its associated LV will be available here.

9. Now only thing left is creation of LUN and mapping of corresponding LV to it so that iSCSI would access it.

For creation of LUN, Navigate to Volumes-->iSCSI Targets

Here you would see that Add button is grayed out. This is due to fact that iSCSI target server service is disabled. To enable the service, navigate to Services and then Click Enable