Managing your storage

This section is about explaining how to manage your storage using ZFS features, the default disk-based file system used on OSv. It would be nice to wrap these commands later on, so as not to make storage management file system dependent.

ZFS/ZPOOL commands

ZFS and ZPOOL command-line tools are available on OSv, then if you're familiar with them, managing the storage will be easier. WARNING: Some options from these commands may not be available yet.

zpool example: Getting I/O statistics from your pools:

$ /PATH_TO_OSV/scripts/run.py -e 'zpool.so iostat'
OSv v0.17-11-ge281199
eth0: 192.168.122.15
               capacity     operations    bandwidth
pool        alloc   free   read  write   read  write
----------  -----  -----  -----  -----  -----  -----
data         155K  9.94G    376    513  8.90M  3.59M
osv         16.8M  9.92G    304    148  12.1M   798K
----------  -----  -----  -----  -----  -----  -----

zfs example: Listing available file systems:

$ /PATH_TO_OSV/scripts/run.py -e 'zfs.so list'
OSv v0.17-11-ge281199
eth0: 192.168.122.15
NAME      USED  AVAIL  REFER  MOUNTPOINT
data      106K  9.78G    31K  /data
osv      16.6M  9.77G    32K  /
osv/zfs  16.4M  9.77G  16.4M  /zfs

How to create an additional file system based on additional virtual disk:

1. Create the image for the additional vdisk using qemu-img:

$ qemu-img create -f qcow2 image.qcow2 10G

2. Change run.py script (locate it at /PATH_TO_OSV/scripts/run.py) to initiate OSv instance with the additional vdisk:

• Change the file parameter from the added line accordingly.

diff --git a/scripts/run.py b/scripts/run.py
index cc8cfda..58b6392 100755
--- a/scripts/run.py
+++ b/scripts/run.py
@@ -116,6 +116,7 @@ def start_osv_qemu(options):
         args += [
         "-device", "virtio-blk-pci,id=blk0,bootindex=0,drive=hd0,scsi=off",
         "-drive", "file=%s,if=none,id=hd0,aio=native,cache=%s" % (options.image_file, cache)]
+    args += [ "-drive", "file=/PATH/TO/IMAGE/image.qcow2,if=virtio"]
 
     if options.no_shutdown:
         args += ["-no-reboot", "-no-shutdown"]

3. Create the pool by executing the following command on your host's terminal:

• /dev/vblk1 is the device associated with your additional vdisk. The second additional vdisk would be /dev/vblk2, and so on.

$ /PATH_TO_OSV/scripts/run.py -e 'zpool.so create data /dev/vblk1'

4. Also on host's terminal, check that the additional file system was created successfully:

$ /PATH_TO_OSV/scripts/run.py -e 'zfs.so list'
OSv v0.17-11-ge281199
eth0: 192.168.122.15
NAME      USED  AVAIL  REFER  MOUNTPOINT
data     92.5K  9.78G    31K  /data
osv      16.6M  9.77G    32K  /
osv/zfs  16.4M  9.77G  16.4M  /zfs

5. From there, /data is available for to be used by the application, and it will be mounted automatically. Enjoy! :-)

TODO: There is a lot to be done on this page, explaining how to create a new file system on additional ZFS pool was the starting point.