NS0-155 Data ONTAP 7-Mode Administrator Questions and Answers

http://backdrift.org/man/netapp/man1/na_sysstat.1.html

-s

Display a summary of the output columns upon termination, descriptive columns such as `CP ty' will not have summaries printed. Note that, with the exception of `Cache hit', the `Avg' summary for percentage values is an average of percentages, not a true mean of the underlying data. The `Avg' is only intended as a gross indicator of performance. For more detailed information use tools such as na_nfsstat, na_netstat, or statit.

https://library.netapp.com/ecmdocs/ECMP1196979/html/man1/na_reallocate.1.html

Using the -p option may reduce the extra storage requirements in a flexible volume when reallocation is run on a volume with snapshots. It may also reduce the amount of data that needs to be transmitted by SnapMirror on its next update after reallocation is performed on a SnapMirror source volume.

https://library.netapp.com/ecmdocs/ECMP1196991/html/GUID-DB31E1F4-60A8-4F34-A1C4-8F79754E4DE2.html

You use the snapvault restore command to restore a backed-up qtree saved to the secondary system. Starting with Data ONTAP 7.3, you can restore the data to an existing qtree on the primary system using baseline restore or incremental restore.

https://library.netapp.com/ecmdocs/ECMP1210206/html/GUID-A865DB95-9418-4ED2-A993-74F347F674A0.html

1. Validate that you can access the remote storage by entering the following command:

aggr status -r

Note: A (level-0 resync in progress) message indicates that a plex cannot be rejoined.

2. Turn on the power to the node at the disaster site. After the node at the disaster site boots up, it displays the following:

Waiting for giveback...(Press Ctrl-C to abort wait)

3. If the aggregates at the disaster site are online, take them offline by entering the following command for each aggregate that was split:

aggr offline disaster_aggr

disaster_aggr is the name of the aggregate at the disaster site.

Note: An error message appears if the aggregate is already offline.

4. Destroy every target plex that is in a level-0 resync state by entering the following command:

aggr destroy plex_name

5. Re-create the mirrored aggregates by entering the following command for each aggregate that was split:

aggr mirror aggr_name -v disaster_aggr

aggr_name is the aggregate on the surviving site’s node.

disaster_aggr is the aggregate on the disaster site’s node.

The aggr_name aggregate rejoins the disaster_aggr aggregate to reestablish the MetroCluster configuration.

6. Enter the following command at the partner node:

cf giveback

The node at the disaster site reboots.

If a scheduled transfer fails (for example, due to network failure), SnapMirror automatically retries the transfer the next minute.

http://hd.kvsconsulting.us/netappdoc/733docs/html/ontap/onlinebk/GUID-511EAA86-069A-42E8-B62E-3168C7F0A83D.html

http://backdrift.org/man/netapp/man1/na_snap.1.html

Snapshots can be made of volumes or aggregates; most commonly the former. The question refers to a file system, or more specifically a volume.

You cannot snapshot directories or qtrees alone.

To convert an asynchronous SnapMirror relationship to a synchronous SnapMirror relationship, on the administration host, edit the snapmirror.conf file on the destination system to change the schedule to sync.

https://library.netapp.com/ecmdocs/ECMP1196991/html/GUID-A78BDBC9-610B-4555-A2DE-CE6861D92614.html

The 'lun' in the path is irrelevant. The 0 at the end of each statement denotes the LUN ID.

LUN IDs must be unique per igroup.

Section: Data Protection

NetApp also recommends that if deduplication is used on the source volume, then it should also be used on the destination volume. However, you are not restricted using deduplication on the source volume only.

The deduplication schedule is not tied to the qtree SnapMirror update. In other words, the deduplication process does not automatically start at the completion of the qtree SnapMirror transfer.

The fingerprint database and the change log files that are used in the deduplication process are located outside of the volume in the aggregate and are therefore not captured in Snapshot copies

http://www.netapp.com/us/media/tr-3505.pdf

https://library.netapp.com/ecmdocs/ECMP1196979/html/man1/na_sysstat.1.html

sysstat reports aggregated filer performance statistics such as the current CPU utilization, the amount of network I/O, the amount of disk I/O, and the amount of tape I/O.

https://library.netapp.com/ecmdocs/ECMP1196979/html/man1/na_options.1.html

nfs.per_client_stats.enable

Enables/disables the collection and display of perclient NFS statistics, as described in na_nfsstat(1). Valid values for this option are on or off. The default value for this option is off.

https://library.netapp.com/ecmdocs/ECMP1196889/html/GUID-83A15F85-92A1-4EA8-A9EC-B9E0E2269E37.html

By aligning the performance of the source and destination, optimal data transfer (aka replication) rates can be attained. Flexvols don't matter, and there is no measurable difference between the performance of a network over a 30m or 3m cable.

http://backdrift.org/man/netapp/man1/na_lun.1.html

lun clone create clone_lunpath [ -o noreserve ] -b parent_lunpath parent_snap

This option causes the file system to remain the same size and not grow or shrink when a SnapMirrored volume relationship is broken, or when a vol add is performed on it. This option is automatically set to be on when a volume becomes a SnapMirrored volume. It will remain on after the snapmirror break command is issued for the volume. This allows a volume to be SnapMirrored back to the source without needing to add disks to the source volume. If the volume size is larger than the file system size, turning off this option will force the file system to grow to the size of the volume. The default setting is off.

http://wafl.co.uk/vol-2/#sthash.DbEHR4YS.dpuf

The snapmirror.access option is the preferred method for controlling snapmirror access on a snapmirror source filer.

http://www.wafl.co.uk/snapmirrorallow/#sthash.4Cb8IqqN.dpuf

Data OnTap can simultaneously serve NAS and SAN protocols. CIFS, NFS, and FC protocol are examples of NAS and SAN protocols respectively.

Data OnTap 7.1 or later does not support DAFS.

DFS provides location transparency and redundancy by allowing shares in multiple different locations to be logically grouped under one folder, or DFS root. While practically a CIFS server shared by a Data OnTap filer can be a DFS target, DFS namespaces can only be hosted on Windows systems.

https://library.netapp.com/ecmdocs/ECMP1196979/html/man5/na_snapmirror.conf.5.html

Each relationship entry of the /etc/snapmirror.conf file is a single line containing space-separated fields.

The entry has this format:

Source destination arguments schedule schedule

This is the schedule used by the destination node for updating the mirror. It informs the SnapMirror scheduler when transfers will be initiated. The schedule field can contain the word sync to specify fully synchronous mirroring, semi-sync to specify semi-synchronous mirroring, or a cron-style specification of when to update the mirror.

visibility_interval

The value for this argument is a number optionally followed by the suffixes: s (seconds), m (minutes) or h (hours). If a suffix is not specified, value is interpreted as seconds. This argument controls the amount of time before an automatic snapshot is created on the source volume that is synchronously mirrored. The value is the number of seconds between automatically created snapshots. The default value is 3 minutes. A small number here can negatively affect the performance of the mirror. This argument is ignored for asynchronous mirrors.

Outstanding (deprecated)

This argument controls the performance versus synchronicity trade-off for synchronous mirrors. The value for this argument is a number followed by the suffixes: ops (operations), ms (milliseconds) or s (seconds). Setting a value less than 10s configures the mirror to run in fully synchronous mode. Setting a value greater than or equal to 10s configures the mirror to run in semi-synchronous mode. This argument is ignored for asynchronous mirrors. Please note that this is a deprecated option. Use the schedule field to specify the synchronous mode for the mirror.

cksum

This controls which checksum algorithm is used to protect the data transmitted by SnapMirror. Currently supported values are "none", "crc32c", and "crc32c_header_only". The value "crc32c_header_only" has been added only for volume SnapMirror and is not supported for synchronous SnapMirror and qtree SnapMirror.

https://library.netapp.com/ecmdocs/ECMP1196979/html/man1/na_sysstat.1.html

https://library.netapp.com/ecmdocs/ECMP1196890/html/man1/na_nfsstat.1.html

nfsstat and sysstat are OnTap commands used for performance information.

sio_ntap_soll is not an OnTap command.

Perfstat is a GUI performance tool, not an OnTap command. Think of PerfMon for Windows to remind you that PerfStat is a Windows tool. Note how many of the ONTAP performance commands end in stat.

https://library.netapp.com/ecmdocs/ECMP1196986/html/GUID-8A91F6A2-61B8-42C3-AEAB7D5AA9BBE9CF.html

If a disk fails and no hot spare disk that exactly matches the failed disk is available, Data ONTAP uses the best available spare. Understanding how Data ONTAP chooses an appropriate spare when there is no matching spare enables you to optimize your spare allocation for your environment.

Data ONTAP picks a non-matching hot spare based on the following criteria (and more; in the link above):

If the available hot spares are not the correct size, Data ONTAP uses one that is the next size up, if there is one.

The replacement disk is downsized (aka right sized) to match the size of the disk it is replacing; the extra capacity is not available.

http://www.wafl.co.uk/cf/

http://wafl.co.uk/options/

Negotiated failover is a general facility which supports negotiated failover on the basis of decisions made by various modules.

cf.takeover.on_disk_shelf_miscompare

This option allows negotiated takeover to be enabled when the cluster nodes detect a mismatch in disk shelf count. By default, this option is set to off.

This option is available only when cluster is licensed and changing the value on one filer automatically changes the value on the partner filer.

You must meet certain prerequisites before using SnapRestore:

- SnapRestore must be licensed on your storage system.

- There must be at least one Snapshot copy on the system that you can select to revert.

- The volume to be reverted must be online.

- The volume to be reverted must not be in use for data replication.

http://hd.kvsconsulting.us/netappdoc/733docs/html/ontap/onlinebk/GUID-A14081A3-9270-47EE-A1C1-EC52D3ABDBD0.html

http://www.brocade.com/downloads/documents/white_papers/Zoning_Best_Practices_WP-00.pdf

Separating the disk and tape devices into separate zones prevents disk RSCNs from impacting tape devices, which tend to be more sensitive to RSCNs.

Best practice is to zone each initiator WWPN to each target WWPN individually.

The rules for the selection of disks or array LUNs, for using as mirrored aggregates, are as follows:

Disks or array LUNs selected for each plex must be in different pools.

The same number of disks or array LUNs must be in both the plexes.

Disks are selected first on the basis of equivalent bytes per sector (bps) size, then on the basis of the size of the disk.

If there is no equivalent-sized disk, Data ONTAP uses a larger-capacity disk, and limits the size to make it identically sized.

Data ONTAP names the plexes of the mirrored aggregate.

https://library.netapp.com/ecmdocs/ECMP1196991/html/GUID-F5F241AF-50C0-4FF3-8C01-96958581C4D9.html

The fstab file reflects the defined filesystem mount paths (including NFS mounts).

Always check network connectivity when a problem arises with a network service.

The exportfs command will display the active exports on the storage system.