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SRDF Commands

December 2nd, 2008 1 comment

The following are SRDF Commands and what they are used for.

Composite SRDF commands

1. Failover:
1. Actions:
1. Write disables (WD) R1
2. Sets link to Not Ready (NR)
3. Write enables R2
2. Command:

symrdf -g ${group} failover

2. Update: Helps to speed up the failback operation by copying invalid tracks before write disabling any disks.
1. Actions:
1. Leaves service state as is.
2. Merges the tracks
3. Copies invalid tracks
2. Command:

symrdf -g ${group} update

3. Failback:
1. Actions:
1. Write disables R2
2. Suspends RDF link
3. Merges the disk tracks.
4. Resumes the link
5. Write enables R1
6. Copies the changed data
2. Command:

symrdf -g ${group} failback

4. Split: Leaves both R1 & R2 in write enabled state.
1. Actions:
1. Suspends the rdf link.
2. Write enables R2
2. Command:

symrdf -g ${group} split

5. Establish:
1. Actions:
1. Write disables R2
2. Suspends the rdf link
3. Copies data from R1 to R2
4. Resumes the rdf link.
2. Command:

symrdf -g ${group} [ -full ] establish

6. Restore: Copies data from R2 to R1
1. Actions:
1. Write disables both R1 & R2
2. Suspends the rdf link.
3. Merges the track tables
4. Resumes the rdf link.
5. Write enables R1
2. Command:

symrdf -g ${group} [ -full ] restore

Singular SRDF commands
1. Suspend: symrdf -g ${group} suspend
2. Resume: symrdf -g ${group} resume
3. Set mode: symrdf -g ${group} set mode sync
symrdf -g ${group} set domino on
symrdf -g ${group} set acp_disk skew 1000

EMC Timefinder Commands

December 2nd, 2008 No comments

The following are the Timefinder Procedural Commands

It outlines everything that needs to be done from start to finish. Realize that for routine operations, some of these steps won’t be needed; however, for the sake of completeness.

Prepare EMC structures

1. Create a Symmetrix disk group

symdg -t [ Regular | RDF1 | RDF2 ] create ${group}

2. Add devices to the disk group

symld -g ${group} add pd /dev/dsk/c#t#d#
symld -g ${group} add dev 01a

3. Associate BCV devices to the disk group

symbcv -g ${group} associate pd ${bcv_ctd}
symbcv -g ${group} associate dev ${bcv_dev}

Establish BCV mirrors

1. ID the logical device names: Timefinder defaults to using the logical device names. You can id the logical device names by:

symmir -g ${group} query

2. First time establish, execute a full establish:

symmir -g ${group} -full establish ${std_log_dev} bcv ${bcv_log_dev}

3. Use symmir query to monitor progress.

symmir -g ${group} query

Break BCV mirrors

1. Types of splits:

1. Instant split: Split is performed in the background after the completion of the split I/O request.
2. Force split: Splits the pair during establish or restore operations; invalid tracks may exist.
3. Reverse split: Resyncs the BCV with the full data copy from its local or remote mirror.
4. Reverse differential split: Enables a copy of only out-of-sync tracks to the BCV from its mirror.
5. Differential split: Enables a copy of only the updated tracks to the BCV’s mirror.

2. Commands:

symmir -g ${group} split
symmir -g ${group} split -instant
symmir -g ${group} split -differential
symmir -g ${group} reverse split -differential

Reestablish or restore BCV mirrors

1. Restore copies data from BCV back to standard pair. >Reestablish, on the other hand, does a differential update of the BCV from the standard device.

2. Commands:
symmir -g ${group} establish Differential reestablish from standard device to BCV
symmir -g ${group} -full restore Full restore of all tracks on BCV to standard device.
symmir -g ${group} restore Differential restore of BCV data to standard device.

The Timefinder Strategies are as follows

1. Maintain BCV mirrors with the standard device; break the mirrors when you want to backup, test, or develop on a copy of the original.

This is probably the most common way of running Timefinder. The advantage is that the split operation will happen almost instantly as the mirrors are fully synced all the time. The disadvantage is that anything towards that happens to the standard device will be reflected in the BCV mirror.

2. Maintain the BCV as a split device to keep an online backup of the original data.

Symcli Basic Commands

December 2nd, 2008 No comments

Following are the Symcli Commands

You can use the man pages for further info.

You can also use the option symxxx -h and will help you navigate around.

Most of the commands come in flavors of three as follows:

Reference Description Example
pd Physical device name /dev/dsk/c3t4d5
dev Symmetrix device name 0FF
ld Symmetrix logical device name DEV001

Examples are as follows:

1. symdev list
2. sympd list
3. symld -g ${group} list

Command Note
symdev Performs operations on a device given the Symmetrix device name.
sympd Performs operations on devices given the devices physical name (c2t0d0)
symgate Performs operations on gatekeeper devices.
symdg Performs operations on Symmetrix device groups
symld Performs operations on devices within a device group
symbcv Performs support operations on BCV pairs
symmir Performs control operations on BCV pairs
symrdf Performs control operations on RDF pairs
symcfg discover Creates a local database of the attached symmetricies.
syminq Shows internal & external devices that the host sees.

Disk Library (DL)

November 29th, 2008 No comments

This is commonly known as VTL (Virtual Tape Library).

There are quite a few variations of the existing 3 models out in the industry that can support various different configurations.

EMC entered the market late on the VTL’s, but along with presence of the front end software from FALCONSTOR, they have done amazing great in the market.

Below is a list of 3 major DL versions in the market and a small comparison chart.