Recovering a file from a snapshot

We recently put together a little test bed of six workstations and 3 servers. All of this equipment is pretty old, but serves our purpose for testing things. I created a ZFS file system called home. Within home, I added a single file called junk which contained a single sentence. I then created a snapshot of "home", and finally restored that junk file:

cd /home

vi junk

zfs snaphot home@tuesday3

cd /home

rm junk

cd /home

cd .zfs

cd snapshot

cd Tuesday3

cp junk /home

Finally, Certified.

After several long months of study, I am finally an Oracle Certified Professional, specifically an Oracle Solaris 10 System Administrator.

Solaris 10 Jumpstart

Our group inherited a bunch of SPARC workstations. It had been a while since I had tackled jumpstart, so with these extra machines, I decided to give it a go. First up was reloading one of the machines with Sol 10. Unfortunately we didn't have the passwords for any of these boxes, but I wanted to start fresh anyway. I took the defaults for the install, but selected ZFS for the export partition. I had a bit of a problem, since these machines will not be allowed on our network. The machine kept wanting to set up its interface. Finally I had to set it up as a standalone.

Over the weekend I picked up a wireless router to use it as a DHCP server. That did the trick, it allowed be to get the network access I would need to set up the jumpstart server and client enviroment.

I had previously downloaded the Solaris 10, update DVD. Many of the direction I found referred to the OS as being on cdroms, with the OS spread over a number of CDs. I took the DVD route. My jumpstart server has an ip address of 192.168.1.101, my client will be 192.168.1.102. 101 is called guajome-dome, while .102 will be called brownwrap.

1. I created a jumpstart directory: mkdir /export/jumpstart

2. Then went to the Tools directory of the install DVD:

cd /cdrom/cdrom0/Solaris_10/Tools

3. Ran the script to create the jumpstart server:

./setup_install_server /export/jumpstart

4. I then had to set up some services on the server, guajome-dome. I modiled /etc/inetd.conf and uncommented the tftp line to allow the client, brownwrap, to tftp to guajome-dome to grab the installation.

Then ran inetconv to add the service to the Service Management Facility (SFM).

Then enabled the service: svcadm enable tftpd

5. I then created a config directory: mkdir /export/jumpstart/config

and added two files to it sysidcfg and rules.

sysidcfg:

network_interface=primary {netmask=255.255.255.0}
security_policy=none
timezone=US/Mountain
system_locale=en_US
install_locale=en_US
name-service=none

rules:

hostname brownwrap - profile -

profile:

install_type initial_install
cluster SUNWCXall
partitionig explicit
filesystem
system_type standalone

Swatch and Logwatch

I had wanted to do some log monitoring without reinventing the world, so I looked around for some log monitoring tools. I found logwatch, which was easy enough to download and install. Had a little problem with configuration, but since I was only interested in watching ssh logins I impleted a command to do just that.

In my looking around, I also found Swatch. Swatch is actually a PERL script. We had a very old very of PERL, so I downloaded and installed the latest from CPAN. I did this because Swatch kept asking for PERL modules which weren't in our version. Once I installed the latest version of PERL, I only needed an additional four modules which I installed. After that I was able to get Swatch up and running and used this command to start it:

/export/home/ramosg/localperl/bin/swatch --tail-file=/var/adm/messages --tail-args -f

Swatch also looks for a config file which I set up in my home directory:


.swatchrc
watchfor /Failed none for/
mail addresses=gregory.c.ramos

Security +

Well, I have taken a break from Linux for a while. New job, new state. One of my job requirements to meet DOD 8570 was to pass Security +. This was not a certification I would have gone after normally, but it was a job requirement, and it did get me back to studying again. So with that in mind, I have decided to pursue some Linux certs. The first up will be Linux+. I'll take that test and see how things go. If I pass it, it will get me not only Linux+, but LPI level 1, and Novell's Certified Linux Professional. So now, back to the books.

Zpooling continued

Now that I have a working mirror again, I will 'repair' the failed disk:

# ls -l /media/Lexar/zfs-testbed/
total 3145729
-rwxrwxrwx 1 root root 512 2010-08-04 14:46 disk1
-rwxrwxrwx 1 root root 1073741824 2010-08-05 08:35 disk2
-rwxrwxrwx 1 root root 1073741824 2010-08-05 08:35 disk3
-rwxrwxrwx 1 root root 1073741824 2010-08-04 14:01 disk4

# rm /media/Lexar/zfs-testbed/disk1

# mkfile 1g /media/Lexar/zfs-testbed/disk1

# ls -l /media/Lexar/zfs-testbed/
total 4194304
-rwxrwxrwx 1 root root 1073741824 2010-08-05 08:48 disk1
-rwxrwxrwx 1 root root 1073741824 2010-08-05 08:45 disk2
-rwxrwxrwx 1 root root 1073741824 2010-08-05 08:45 disk3
-rwxrwxrwx 1 root root 1073741824 2010-08-04 14:01 disk4
#

Now time to add in the two 'spare disks' to the mirror:

# zpool add clifford mirror /media/Lexar/zfs-testbed/disk1 /media/Lexar/zfs-testbed/disk4

I'll use a different command to take a look at the mirror:

# zpool iostat -v clifford
capacity operations bandwidth
pool used avail read write read write
---------------------------------- ----- ----- ----- ----- ----- -----
clifford 150K 1.98G 0 0 1 826
mirror 120K 1016M 0 0 1 823
/media/Lexar/zfs-testbed/disk2 - - 0 0 62 878
/media/Lexar/zfs-testbed/disk3 - - 0 0 41 878
mirror 29.5K 1016M 0 0 0 565
/media/Lexar/zfs-testbed/disk1 - - 0 0 319 31.4K
/media/Lexar/zfs-testbed/disk4 - - 0 0 319 31.4K
---------------------------------- ----- ----- ----- ----- ----- -----

#

Creation of zpool

A while back I created a zpool. since I didn't have unused disks lying around, I used a 32 GB usb drive. I created four files to be treated as separate disks so that I could create a zpool and mirror disks. Although this would not really offer the protection of mirroring, it did allow me to become familiar with zpools and zfs filesystems, though I had previously created a ZFS filesystem on a spare disk.

The first thing I did was create the four disk files. The USB drive was mounted as /media/Lexar. I then created a sub-directory called 'zfs-testbed'. I "cd'd" to it and created the files:

mkfile 1g /media/Lexar/zfs-testbed/disk1
mkfile 1g /media/Lexar/zfs-testbed/disk2
mkfile 1g /media/Lexar/zfs-testbed/disk3
mkfile 1g /media/Lexar/zfs-testbed/disk4

That created four 1 GB files.

Next I created a zpool consisting of the one 'dive' :

zpool create gregory /media/Lexar/zfs-testbed/disk1

zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
gregory 1016M 73K 1016M 0% ONLINE -
rpool 148G 17.1G 131G 11% ONLINE -
zfs-ramos 148G 12.4G 136G 8% ONLINE -

Then I destroyed the pool, so I could create a mirror:

zpool destroy gregory

zpool create clifford mirror /media/Lexar/zfs-testbed/disk1 /media/Lexar/zfs-testbed/disk2


zpool list
NAME SIZE USED AVAIL CAP HEALTH ALTROOT
clifford 1016M 74.5K 1016M 0% ONLINE -
rpool 148G 17.1G 131G 11% ONLINE -
zfs-ramos 148G 12.4G 136G 8% ONLINE -


Now I intentionally destroy the label:

dd if=/dev/random of=/media/Lexar/zfs-testbed/disk1 bs=512 count=1

zpool status
pool: clifford
state: DEGRADED
status: One or more devices could not be used because the label is missing or
invalid. Sufficient replicas exist for the pool to continue
functioning in a degraded state.
action: Replace the device using 'zpool replace'.
see: http://www.sun.com/msg/ZFS-8000-4J
scrub: scrub completed after 0h0m with 0 errors on Wed Aug 4 14:47:35 2010
config:

NAME STATE READ WRITE CKSUM
clifford DEGRADED 0 0 0
mirror DEGRADED 0 0 0
/media/Lexar/zfs-testbed/disk1 UNAVAIL 0 0 0 corrupted data
/media/Lexar/zfs-testbed/disk2 ONLINE 0 0 0


Now detach the bad disk:

zpool detach clifford /media/Lexar/zfs-testbed/disk1


Attach a new 'disk':

zpool attach clifford /media/Lexar/zfs-testbed/disk2 /media/Lexar/zfs-testbed/disk3

# zpool status clifford
pool: clifford
state: ONLINE
scrub: resilver completed after 0h0m with 0 errors on Wed Aug 4 14:55:33 2010
config:

NAME STATE READ WRITE CKSUM
clifford ONLINE 0 0 0
mirror ONLINE 0 0 0
/media/Lexar/zfs-testbed/disk2 ONLINE 0 0 0
/media/Lexar/zfs-testbed/disk3 ONLINE 0 0 0 85K resilvered

errors: No known data errors


Here I rebooted to complete the process. After the reboot:

zpool status clifford
pool: clifford
state: ONLINE
scrub: none requested
config:

NAME STATE READ WRITE CKSUM
clifford ONLINE 0 0 0
mirror ONLINE 0 0 0
/media/Lexar/zfs-testbed/disk2 ONLINE 0 0 0
/media/Lexar/zfs-testbed/disk3 ONLINE 0 0 0

errors: No known data errors