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July 14th, 2009 03:00

What is the meaning of SA / RA /LNK status in the output of Symrdf commands

Hi...

When I run command "symrdf -list", I notice there is a column about "status" which there are 3 sub columns inside this column that is SA, RA and LNK. I would like to know what is the meaning and difference of each status.

Thank you in advance.

Local Device View
-------------------------------------------------------------------------
STATUS MODES RDF S T A T E S
Sym RDF --------- ----- R1 Inv R2 Inv ----------------------
Dev RDev Typ:G SA RA LNK MDA Tracks Tracks Dev RDev Pair
---- ---- ------ --------- ----- ------- ------- --- ---- -------------

0023 0023 R2:2 RW RW NR S.. 0 0 RW RW Split
0024 0024 R2:2 RW RW NR S.. - - RW RW Split
0025 0025 R2:2 RW RW NR S.. 0 0 RW RW Split
0ED0 0C0D R2:2 RW RW NR S.. - - RW RW Split
0ED1 0C0E R2:2 RW RW NR S.. - - RW RW Split
0ED2 0C17 R2:2 ?? RW NR S.. 0 0 RW RW Split
0ED3 0C18 R2:2 ?? RW NR S.. - - RW RW Split
0ED4 0C19 R2:2 ?? RW NR S.. - - RW RW Split
0ED5 0C1A R2:2 ?? RW NR S.. - - RW RW Split
0ED6 0C1B R2:2 ?? RW NR S.. 0 0 RW RW Split
0ED7 0C1C R2:2 ?? RW NR S.. - - RW RW Split
0ED8 0C1D R2:2 ?? RW NR S.. - - RW RW Split
0ED9 0C1E R2:2 ?? RW NR S.. - - RW RW Split
0EDA 0887 R2:2 RW RW NR S.. 10 0 RW RW Split
1170 0B00 R2:2 RW WD RW S.. - - WD RW Synchronized
1171 0B01 R2:2 RW WD RW S.. - - WD RW Synchronized
1172 0B02 R2:2 RW WD RW S.. - - WD RW Synchronized
1173 0B03 R2:2 RW WD RW S.. - - WD RW Synchronized
1174 0B04 R2:2 RW WD RW S.. - - WD RW Synchronized

2 Intern

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448 Posts

July 14th, 2009 06:00

0023 0023 R2:2 RW RW NR S.. 0 0 RW RW Split

source device 23
target device 23
device type is R2 (target)
RDF Group 2
RW = read/write enabled SA
RW = read write enabled RA
NR = not ready on link
S = Synchronous mode
RW = read/write enabled local dev
RW = read/write enabled remote dev
Split = the rdf devices are currently in the split state no data is transmitting and both sides are available to hosts

sorry forgot there are 0 tracks owed on either side.

Message was edited by:
RobertDudley

10 Posts

July 15th, 2009 21:00

Thank you very much for you reply but I have one more questions. What is SA and RA means?


Thank you again.

2 Intern

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2.8K Posts

July 16th, 2009 01:00

SA = Scsi Adapter (front end, if you prefer)

RA = Remote Adapter (RDF processors if you prefer)

2 Intern

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448 Posts

July 16th, 2009 11:00

FYI as Stephano stated SA = SCSI adapter and is used in place of FA = Fiber Adapter in some areas of EMC displays.

2 Intern

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2.8K Posts

July 17th, 2009 04:00

I think mixing FA/SA in solution enabler output is at least misleading ... But if you think that a Fiber Adapter acts as a very special Scsi Adapter while talking to the hosts, it's easier to understand why we use to mix FA and SA. :-)

4 Operator

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2.1K Posts

July 21st, 2009 08:00

I agree that it is misleading, but I'll bet they did it on purpose to maintain consistency from the days when SA were way more common.

And in support of their thought process, as far as most operating systems are concerned, an FA is just a fancy SA anyway. The same way most OSes think that SAN attached disk provided through an HBA and FC fabric is just locally attached SCSI disk.

17 Posts

July 21st, 2009 23:00

Still Iam confused like what RW/WD on SA/RA for a device indicates exactly. Dont say RW means Read/Write enabled and WD means WriteDisabled.

2 Intern

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448 Posts

July 22nd, 2009 05:00

When you have an SRDF relationship devices can be either write enabled or write disabled to host (read only mode) depending on wether or not you are transferring data. In normal srdf operation the source device is write enabled to the host and the target is write disabled to the host. The target device is then read only as you would not want to write data to the target from a host and be synchronizing data from the source at the same time. When you stop the synchronization from the source by using the SPLIT command it will write enable the target device and leave the source device write enabled. Since devices are mapped on an SA/FA and the RDF channel it will show you the read write status from the perspective of each director.

One way to look at srdf is that you are creating an additional mirror to your source device it just happens that this mirror is in a different array. This additional mirror is independent and can be operated on by the user depending on its mode.

Normal SRDF operation

Source devices are set to read/write which gives the local host full device access
Target devices are set to write disabled to its local hosts (read only mode)

SRDF relationship SPLIT

Source devices are set to read/write which gives the local host full device access
target devices are set to read/write which gives the local host full device access
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