Thursday, March 26, 2009

NetApp Tips and few commads

SnapManager for VI 1.0 (Virtual Infrastructure)

In Vmware environments:

1. snapshots may not be granular enough.

2. vmware is best in NFS than ISCSI.

3. Traditional backups disadvantages.. (i) dont match your VI (ii) No cpu power left on the server.

4. Recommended.. only 4 snapshot copies a day.

5. how SMVI works.. (i) Backup initiated. (ii) Vm snapshot copy created. (iii) Snapmanager for VI triggers instant NetApp snapshot. (iv) vm snapshot removed.

6. only VMFS/NFS support. No RDM support.

7. Protocols - ISCSI, FCP, NFS.

8. snapmirror is integrated.

9. Backup scheduling and retention policies

10. SMVI only support netapp storage.

11. Efficiently meet the backup and DR needs of your ESX environment. (i) Leverages netapp snapshot tech (ii) provides a way to restore VM and data stores

Snap Manager

SnapManager provides rapid online backup and near instantaneous restoration of Exchange databases by using online Snapshot™ technology that is part of the Data ONTAP® software and integrating the Microsoft Exchange backup and restore APIs and VSS. SnapManager can also leverage the SnapMirror capabilities of storage systems to provide on-site or off-site SnapManager backup set mirroring for disaster recovery.

Data management:

SnapManager supports the following data management capabilities:

· Migrating Exchange databases and transaction logs to LUNs on storage systems

· Backing up Exchange databases and transaction logs from LUNs on storage systems

· Verifying the backed-up Exchange databases and transaction logs

· Managing the SnapManager backup sets

· Restoring Exchange databases and transaction logs from previously created SnapManager backup sets

· You can use SnapManager to create offline archives of Snapshot copies containing Exchange backup sets for long term or remote backup storage.

Three different archive methods are supported:

1. Manually initiated archival using NDMP (Network Data Management Protocol) or the storage system's dump command

2. Manually initiated archival using a Windows backup utility

3. Automatic archival using the Run Command After Operation feature with your backup operation

The SnapVault software can be used to archive backup sets.

What Snap Manager does NOT do:

SnapManager 4.0 for Microsoft Exchange does not support the following uses:

  • SnapManager does not support the capability to restore individual mailboxes or public folders.
  • SnapManager does not support SnapDrive versions prior to 4.2.1.
  • SnapManager does not create or restore backups of Microsoft Exchange databases that are stored on storage devices that are provided by companies other than NetApp.
  • SnapManager does not support Microsoft Windows 2000.
  • SnapManager does not restore Microsoft Exchange Server 2003 and Microsoft Exchange Server 2007 databases to an alternate location.
  • SnapManager does not backup and restore Microsoft Exchange 5.5 and Exchange 2000 databases.
  • SnapManager is not supported for use on Windows Server 2003 IA-64 edition.

VIFS on NetApp

Vifs (Virtual interfaces) are used for multi-homing and load balancing. A Single mode vif is for failovers only and Multi-mode vif is for load balancing, but you can use a combination of multi-mode and single mode to be fully redundant and load balanced.

For more information on VIFS please check the NetApp now site.

To create a single mode vif

vif create single sample-vif0 e0a e0c

To configure an interface to use a vif

ifconfig sample-vif0 `hostname`-pub mediatype auto netmask wins partner cluster-vif0

Make sure you reference the vif name not the interface name

To view all interfaces including vifs

Ifconfig –a

To view a single interface or vif (note you must view the vif in order to see ip address)

Ifconfig sample e0a

Ifconfig sample-vif0

To view all vifs status

vif status

To view single vif

vif status sample-vif0

To view statistics

vif stat sample-vif0

If you need to remove an interface from a vif

vif delete sample-vif0 e0c (This will remove e0c from sample-vif0)

To favor one interface in a VIF (this always be the one that's used if up, if it ever goes down and then comes back up it will fail back to it)

vif favor e0a

To see more commands type the following at a command prompt.

Vif ?

Tuesday, March 24, 2009

NetApp usable space calculation formula

NetApp RAW to usable space calculation formula

All of sudden today I got a question "Is there any quick formula to calculate the usable capacity for NetApp filer?" in all my career I never had to come across for any such kind of formula so curiously I started hunting on web and found a number of sites offering such tool but most of them either dead or pointing to a tool developed by Nick Bernstein. This is a small tool available for free download, where you have to select the disk, raid and some other options and you get a good numbers of usable space from your raw space. Although it gives a very close figures and sometime actual number, but I found it's not all, as there are some more constraints which one has to keep in mind while quoting usable space.

So I started hunting more on net and came across one blog from Jim of HP, where he is criticising the NetApp's not so called clear approach of giving any formula for same and after that a number of following comments by some NetApp big-shots.

After going through post and accusations made by each other on their product I found an easy to understand formula with example posted by NetApp guy. Now below is the formula given by them where I have added my points which I think is required while calculating usable size.

So first thing first, as we all know that space advertised by manufacturers are in base10 formula which is just a marketing funda but we use in base2 formula which is the actual space your system sees once you connect the disk. So I will use GB forms in base2 which is the actual space we can use.

Let's take example of 20 FC disk of 144GB which after converting in base2 number comes to (136000MB/ 1024) 132.8GB x 20 = 2656 GB
(You can check the base2 size of each disk in sysconfig -r command)

Now we will use the disks in Raid-DP so each raid group will reserve 2 disks as parity, so now we have space left-over with 20 - 2 x 132.8 = 2390 GB
(Please note that here I have taken the example of FC disk where maximum number of disks limit per RG is 28, check the NetApp Storage management guide under topic Maximum and Default Raid Group Size or see the online version on now site here)

As NetApp system stores an additional checksum of 8bytes for every 512 bytes of data, which is ~1.5% overhead or 35GB in this case. So we are leftover with 2355GB.

Now reduce 10% for WAFL overhead, so it comes to 2120GB

Now change the default aggregate snapshot reserve from 2% to 0%. Why? Because aggregate level snapshots are primarily used for metrocluster.

So to summarize that let's see the an easy step by step calculation formula
1. Check available disk capacity in base2 number (a)
2. Number of disks - hot spares - Parity disk required by raid group (depends on raid type and disk type+number) = number of disks will be used in aggregate (b)
3. a * b = Raw space available (c)
4. c - 1.5% = Space after additional checksum overhead (d)
5. d - 10% = Space after WAFL Overhead (e)

So in nutshell 88.65% is usable space after multiplying with the value of raw space in base 2 value

Link from netapp from raw to usable conversion a good read if you want to know anything further

On SATA disks space used for checksum in BCS type is more than 11%, but if you use ZCS the net loss from checksums is a little under 2% which is consumed from the wafl reserve
Post updated following changes in release of ONTAP 8.1.