How to quit SSH session by typing 'exit' in ONTAP

Just a little trick to remove annoyance for new NetApp admin.

Usually when we want to terminate a SSH session on ONTAP you type Ctrl+D as typing 'exit' returns with message to press 'Ctrl+D' to exit. It's perfectly fine and there isn't any harm as that gracefully closes the session but as most of us are more use to of typing 'exit' to terminate the session, find it odd. 

So for those who prefer typing 'exit' to close the session can do so by enabling telnet.distinct.enable option.
Default setting for this option is off which in effect mirrors telnet and console session but if you don't use this feature, which I believe most of us don't, can enable it and feel more at home.

How to restore data from aggregate snapshot

Today one of our user found himself in wet pants when he noticed his robocopy job has overwritten a folder, rather than appending new data to it. Being panicked he run to me looking for any tape or snapshot backup of his original data, which unfortunately wasn’t there as previously he confirmed that they don’t need any kind of protection.

Now at this time I had only place left where I can recover the data, aggregate level snapshots; so I looked at aggregate snapshots and saw it goes back to time when he had data in place. Knowing that the data deleted from volume is still locked in aggregate’s snapshot I was feeling good that I have done a good job by having some space reserved for aggregate level snapshot, which no one ever advocated.

Now the next step is to recover the data, but problem was that if I revert aggregate using “snap restore –A” then all the volumes in that aggregate will be reverted which will be bigger problem. So had to go on a different way, use aggregate copy function to copy the aggregate’s snapshot to an empty aggregate and then restore the data from there.

Here’s the cookbook for this.

Pre-checks:

• The volume you lost data from is a flexible volume 
• Identify an aggregate which is empty so it can be used for destination (could be on another controller also) 
• Make sure the destination aggregate is either equal or larger than source aggregate 
• /etc/hosts.equiv has entry for the filer you want to copy data to and /etc/hosts has its IP address added, in case of copying on same controller loopback address (127.0.0.1) should be added in /etc/hosts file and local filername should be in hosts.equiv file 
• Name of aggregate’s snapshot which you want to copy 

Example:

Let’s say the volume we lost data was ‘vol1’, the aggregate which has this volume is ‘aggr_source’, the aggregate’s snapshot which has lost data is ‘hourly.1’ and empty aggregate where we will be storing data to is ‘aggr_destination’

Execution:

• Restrict the destination aggregate using  ‘aggr restrict aggr_destination’ 
• Start the aggregate data copy using ‘aggr copy start –s hourly.1 aggr_source aggr_destination’ 
• Once the copy is completed online the aggregate using ‘aggr online aggr_destination’ 
• If you have done copy on same controller, system will rename the volume ‘vol1’ of ‘aggr_destination’ to ‘vol1(1)’ 
• Now export the volume or lun and you have your all lost data available.

So here’s the answer to another popular question, why do I need to reserve space for aggregate level snapshot. Do you have the answer now?

How to do host/user/group or netgroup from filer

Often we want to do nslookup for a host or NIS/LDAP lookup for a user or group for troubleshooting purpose. You have a unix system handy and you do it from there however what if you suspect results are not same as what your filer may be getting?

If you are troubleshooting CIFS issue, you are in luck with command 'cifs lookup' however, if you are dealing with DNS or NFS issue then you are out of luck, unless you go into advanced mode. Yes, you go inside advance mode and you get access to lot of other commands including one very nifty command 'getXXbyYY', which is incredibly useful but hidden from the view of admins for some strange reason, really I am not sure why NetApp thinks this shouldn't be available to end user as every time I do troubleshooting I feel the need of this and by no way I see this to be making any sort of changes on filer.

Anyway here's the command, though command says using "man na_getXXbyYY" for additional info however I couldn't locate it on systems therefore I use

test1*> getXXbyYY help
usage: getXXbyYY
Where sub-command is one of
gethostbyname_r
gethostbyaddr_r
netgrp
getspwbyname_r
getpwbyname_r
getpwbyuid_r
getgrbyname
getgrbygid
getgrlist

For more information, try 'man na_getXXbyYY'

Please remember this command is not available in admin mode and search order depends of your /etc/nsswitch.conf entry, so before you start thinking that this isn't working as expected please check these two things first.

Though all the subcommands are self explanatory however I have added small description for each of them.

gethostbyname_r - Resolves host name to IP address from configured DNS server, same as nslookup
gethostbyaddr_r - Retrieves IP address for host name from configured DNS server, same as reverse lookup
netgrp - Checks group membership for given host from LDAP/Files/NIS
getspwbyname_r - Displays user information using shadow file
getpwbyname_r - Displays user information including encrypted password from LDAP/Files/NIS
getpwbyuid_r - Same as above however you provide uid in this command rather than user name
getgrbyname - Displays group name and gid from LDAP/Files/NIS
getgrbygid - Same as above however you provide gid in this command rather than group name
getgrlist - Shows given user's gid from LDAP/Files/NIS

Examples:

test1*> getXXbyYY gethostbyname_r landinghost1
name: landinghost1
aliases:
addresses: 10.21.242.7

test1*> getXXbyYY gethostbyaddr_r 10.21.242.7
name: landinghost1
aliases:
addresses: 10.21.242.7

test1*> getXXbyYY netgrp support-group testhost1
client testhost1 is in netgroup support-group

test1*> getXXbyYY getpwbyname_r root
pw_name = root
pw_passwd = _J9..gsxiYTAHEtV3Qnk
pw_uid = 0, pw_gid = 1
pw_gecos =
pw_dir = /
pw_shell =

test1*> getXXbyYY getpwbyuid_r 0
pw_name = root
pw_passwd = _J9..gsxiYTAHEtV3Qnk
pw_uid = 0, pw_gid = 1
pw_gecos =
pw_dir = /
pw_shell =

test1*> getXXbyYY getgrbyname was
name = was
gid = 10826

test1*> getXXbyYY getgrbygid 10826
name = was
gid = 10826

test1*> getXXbyYY getgrlist wasadmin
pw_name = wasadmin
Groups: 10826

Execute command from a file on Ontap

Occasionally we want to quickly or periodically run a set of pre defined commands on filers, like when we are making little change in network configuration and want to minimize the network down time or when we are creating a volume and know snap reserve, snap schedule, de-dupe, autosize or anything else which needs to be changed after every volume creation. If you are executing commands from unix terminal then a better way would be to keep all the commands in a text file and would do something like

bash>for $i in vol1
>do
>snap sched $i 0
>snap reserve $i 0
>blah $i
>blah $i
>done

and everything would be done, but imagine how would you do if you are doing through console. Unfortunately Ontap doesn't supports any kind of script not even for loop so we have to run each and every line of command either by typing on console or doing a copy-paste from text file from our desktop.

However there is a better way, use notepad to create set of command as you would execute on console with correct order, copy it off to filer and use 'source' command to execute each and every line from it. I know it's not such a brilliant idea as still you have to copy and paste everything to a file on filer however it's wee better than executing each and every command on console.

Think about you have to re-run /etc/rc so either you can use 'rdfile /etc/rc' to print everything on console and copy all the the line and execute on console or just run 'source /etc/rc' and let it run all the commands for you. You can also use 'source -v /etc/rc' to print the commands on console but not to execute, just to get an idea if there are any junk characters or any unwanted command inside the file, just as a precaution you better be sure that all the commands are valid and correct as if a command fails source doesn't stops there and just goes to next command in list.

Use it and I am sure you will like it next time when you are making some changes on filer which needs ten different commands to be executed.

How to check unplanned downtime detail for a NetApp filer

Every now and then someone ask us what is uptime of system and we just type 'uptime' on system console to get the detail instantly.


This is really handy command to know when the system was last rebooted and how many operations per protocol it has served since then. Wouldn't our life be little easy if managers get satisfy with this detail? Alas! but that doesn't happen and they ask us to give all the details since we have acquired the system or 1st January and then we go back to our excel sheet or ppt we have created as part of monthly report to pull the data.


How about if we can get same information from system with just a command, wouldn't that be cool. Fortunate enough we have little known command 'availtime' right inside Ontap which just do the exact same function and specifically created after thinking about our bosses.


HOST02*> availtime full
Service statistics as of Sat Aug 28 18:07:33 BST 2010
 System  (UP). First recorded 68824252 secs ago on Mon Jun 23 04:16:41 BST 2008
         Planned   downs 31, downtime 6781737 secs, longest 6771328, Tue Sep  9 15:07:33 BST 2008
         Uptime counting unplanned downtime: 100.00%; counting total downtime:  90.14%
 NFS     (UP). First recorded 68824242 secs ago on Mon Jun 23 04:16:51 BST 2008
         Planned   downs 43, downtime 6849318 secs, longest 6839978, Wed Sep 10 10:11:43 BST 2008
         Uptime counting unplanned downtime: 100.00%; counting total downtime:  90.04%
 CIFS    (UP). First recorded 61969859 secs ago on Wed Sep 10 12:16:34 BST 2008
         Planned   downs 35, downtime 17166 secs, longest 7351, Thu Jul 30 13:52:25 BST 2009
         Uptime counting unplanned downtime: 100.00%; counting total downtime:  99.97%
 HTTP    (UP). First recorded 47876362 secs ago on Fri Feb 20 14:08:11 GMT 2009
         Planned   downs 8, downtime 235 secs, longest 53, Wed Jan 20 14:10:18 GMT 2010
         Unplanned downs 16, downtime 4915 secs, longest 3800, Mon Jul 27 16:01:02 BST 2009
         Uptime counting unplanned downtime:  99.98%; counting total downtime:  99.98%
 FCP     (DOWN). First recorded 68817797 secs ago on Mon Jun 23 06:04:16 BST 2008
         Planned   downs 17, downtime 44988443 secs, longest 38209631, Sat Aug 28 18:07:33 BST 2010
         Unplanned downs 6, downtime 78 secs, longest 21, Fri Feb 20 15:24:44 GMT 2009
         Uptime counting unplanned downtime:  99.99%; counting total downtime:  34.62%
 iSCSI   (DOWN). First recorded 61970687 secs ago on Wed Sep 10 12:02:46 BST 2008
         Planned   downs 21, downtime 38211244 secs, longest 36389556, Sat Aug 28 18:07:33 BST 2010
         Uptime counting unplanned downtime: 100.00%; counting total downtime:  38.33% 


I am not sure why NetApp has kept this command in Advanced mode but once you know this command I bet next time you will not refrain yourself going inside advance mode to see how many unscheduled downtime you had since last reset.


A shorter version of this command is just 'availtime' it also shows the same information as 'availtime full' however it truncates letters from output and denotes  Planned with P and Unplanned with U which is very good if you want to pass it in script. 

HOST04*> availtime
Service statistics as of Sat Aug 28 18:07:33 BST 2010
 System  (UP). First recorded (20667804) on Wed Sep 23 09:35:49 GMT 2009
         P  5, 496, 139, Fri Dec 11 15:58:19 GMT 2009
         U  1, 1605, 1605, Wed Mar 31 17:01:41 GMT 2010
 CIFS    (UP). First recorded (20666589) on Wed Sep 23 09:56:04 GMT 2009
         P  7, 825, 646, Thu Jan 21 19:08:03 GMT 2010
         U  1, 77, 77, Wed Mar 31 16:34:54 GMT 2010
 HTTP    (UP). First recorded (20664731) on Wed Sep 23 10:27:02 GMT 2009
         P  3, 51, 22, Thu Jan 21 19:17:25 GMT 2010
         U  4, 203, 96, Thu Jan 21 19:08:03 GMT 2010
 FCP     (UP). First recorded (20477735) on Fri Sep 25 14:23:38 GMT 2009
         P  3, 126, 92, Thu Jan 21 19:07:57 GMT 2010
         U  4, 108, 76, Wed Mar 31 16:34:53 GMT 2010

In order to reset the output use 'reset' switch and it will zero out all the counters, make sure you have recorded the statistics before you reset the counters as once you reset the counters you will not be able to get details of system uptime since system was built so you may like to do only after you acquire a new system, have done all the configuration and now it's the time for it to serve user requests.

How to copy files in Ontap

As soon as someone asks this question we all say ‘use ndmpcoyp’ but what if you don’t have any network adapters configured, will ndmpcoyp work?

No; ndmpcopy is very useful if you want to copy a file or a whole volume however one thing very few people know that it doesn’t work if you don’t have loopback adapter configured because ndmpcopy passes all the data through lo adapter so it’s not only dependent on lo’s availability, its speed also. So how do you copy the data if lo is not available?

The answer is simple, use dd, just an old fashioned unix command which does lot of thing, not only it can copy the file with full pathname you can even use block number and disk number and the best part, syntax is simple ‘if’ for from and ‘of’ for to.

It can be used not only for copying file around the system, in fact you can use it for testing I/O and copying file from snapshot also and this command can be used regardless of permission.

A little note, if you are afraid of going in advanced or diagnostic mode better keep use rdfile and wrfile because this command is not available in admin mode so you have to go in advanced mode to use this.

Here’s the syntax of this command.

dd [ [if= file ] | [ din= disknum bin= blocknum ] ] [ [of= file ] | [ dout= disknum bout= blocknum ] ] count= number_of_blocks

Another note, if you are using count make sure you are using in multiply of 4 because a WAFL block size is 4k.

Example:

sim1> priv set advanced
sim1*> dd if=/vol/vol0/.snapshot/hourly.2/etc/snapmirror.conf of=/vol/vol0/etc/snapmirror.conf1