[cifs-protocol] [REG:111092948476937] FRSRPC: questions about schedule

Tue Oct 25 10:09:02 MDT 2011

Hi Matthieu:
Please find the answers to your questions as follows>

Q. Ok and what happen if a downstream partner tries to join when the schedule is closed ?
A. If the schedule is trigger schedule (sysvol connection between sites), the upstream partner will ignore the schedule and join will be successful as mentioned in Ms-FRS1 section “3.3.2.1.1   SYSVOL Connection ScheduleTimer”:

“When a triggering schedule is used, the upstream partner ignores its schedule and responds to any request by the downstream partner. When the schedule 
closes, the upstream partner unjoins the connection only after the current contents of the outbound log, at the time of join, have been sent and acknowledged.”

For non-trigger schedule, the command is ignored if schedule is not open.

Q. > By “upstream partner unjoins the connection” does not mean that upstream partner sends CMD_UNJOIN_REMOTE command. This is in context of a normal sync and refers to an internal state where upstream partner is in “join” state when replication is going on and when replication is complete, the connection is in “unjoin” state. The “unjoin” here refers to stuff like invalidating the join GUID, incrementing the unjoin counters, freeing the outbound version vectors etc.
Ok this is clear, thanks for the precision. Should this information be added to the FRS1.pdf ?

A. A mentioned in section 2.2.3.6.2   COMM_COMMAND (and on other places) that CMD_UNJOIN_REMOTE is sent only for initial sync (VVJOIN). So in case of non-vvjoin joins, unjoin is implicit. In case of trigger schedule, this “implicit unjoin” happens when all the contents of outbound log at the time of join are synced. In case of non-trigger schedule, the “implicit unjoin” happens at the close of the schedule as mentioned in section 3.3.2.1.2:

“When the schedule closes, FRS unjoins the connection.”

Q. Ok that was not 100% clear for me that when a schedule period is open it's for 15 minutes at least (if you have only 1 period).
Should this precision be added to the document ?

A. This is mentioned in the document. In section “3.3.2.1.1   SYSVOL Connection ScheduleTimer” it is stated that:
“When set to one time per hour, replication MUST start at 0:00 and ends at 0:15.”

Please let me know if it answers your question.

Regards,
Obaid Farooqi
Escalation Engineer | Microsoft

-----Original Message-----
From: Matthieu Patou [mailto:mat at samba.org] 
Sent: Friday, October 21, 2011 4:06 PM
To: Obaid Farooqi
Cc: pfif at tridgell.net; cifs-protocol at samba.org; MSSolve Case Email
Subject: Re: [REG:111092948476937] FRSRPC: questions about schedule

On 21/10/2011 01:05, Obaid Farooqi wrote:
> Hi Matthieu:
> I am providing the answers in the Q&A format to your questions:
>
> Q. Given the fact that, from my understanding, FRS is pushed based, what's the implication of this ?
> Because even if it's the downstream partner that is sending change notification it has to wait for the upstream to create a connection and once it's done it can start to send files.
> Also the unjoin command is send by the one who created the connection that is to say the downstream partner, so how can the upstream partner "unjoin" the connection ?
>
> A. I will use the following definitions (MS-FRS1 Glossary) of upstream and downstream partner to explain what the paragraph means.
> Downstream Partner: The partner that receives change orders, files, and folders.
> Upstream Partner: The partner that sends out change orders, files, and folders.
>
> The sentence “When a triggering schedule is used, the upstream partner ignores its schedule and responds to any request by the downstream partner.” means that even if the schedule is closed as per the configuration, replication will continue till all the change orders in the outbound log are done. The “request by the downstream partner” is like CMD_SEND_STAGE that a downstream partner sends in the course of a sync. It does not mean that the exchange is initiated by downstream partner. The CMD_REMOTE_CO is still sent by upstream partner at the beginning of the schedule open.
Ok and what happen if a downstream partner tries to join when the schedule is closed ?
>
> If the schedule is “non-triggering”, the replication will stop even if there are outstanding change orders in the outbound log and upstream partner will ignore request from downstream partner to continue replication.
>
> By “upstream partner unjoins the connection” does not mean that upstream partner sends CMD_UNJOIN_REMOTE command. This is in context of a normal sync and refers to an internal state where upstream partner is in “join” state when replication is going on and when replication is complete, the connection is in “unjoin” state. The “unjoin” here refers to stuff like invalidating the join GUID, incrementing the unjoin counters, freeing the outbound version vectors etc.
Ok this is clear, thanks for the precision. Should this information be added to the FRS1.pdf ?
>
> Q. Also can you clarify what's the meaning "when the schedule close" means exactly ? I understand that by default you have a schedule open every 15 minutes, but for how long it is open ?
>
> A. A schedule can only open at minutes 0, 15, 30 and 45 of any hour of the day. Once it is open, it is open for minimum 15 minutes. So, for example, you configured the schedule to open at 5:00PM and 5:15PM. In this case the schedule will open at 5:00PM and will close at 5:30PM and will be open for 30 minutes. If you configure contiguous 15 minutes periods then schedule will open at the beginning of the first 15 minute period and will close at the end of last 15 minute period.
>
> As mentioned in MS-FRS1 section “2.3.1.2   NTFRS Replica Set Object”, the schedule is an 84-byte array. Each byte corresponds to two hours and the first byte corresponds to first two hours of Sunday. If the value of first byte is 0x0F and the rest of the bytes are all zero, the schedule will open at 0:00 on Sunday and will close on 1:00AM on Sunday.
Ok that was not 100% clear for me that when a schedule period is open it's for 15 minutes at least (if you have only 1 period).
Should this precision be added to the document ?

Thanks.

Matthieu.
>
> Please let me know if it does not answer your question.
>
> Regards,
> Obaid Farooqi
> Escalation Engineer | Microsoft
>
> Exceeding your expectations is my highest priority.  If you would like to provide feedback on your case you may contact my manager at nkang<at>  microsoft dot com.
>
> -----Original Message-----
> From: Obaid Farooqi
> Sent: Friday, September 30, 2011 2:30 PM
> To: 'mat at samba.org'
> Cc: pfif at tridgell.net; cifs-protocol at samba.org; MSSolve Case Email
> Subject: RE:[REG:111092948476937] FRSRPC: questions about schedule
>
> Hi Matthieu:
> I'll help you with this issue and will be in touch as soon as I have an answer.
>
> Regards,
> Obaid Farooqi
> Escalation Engineer | Microsoft
>
>
>
> -----Original Message-----
> From: Matthieu Patou [mailto:mat at samba.org]
> Sent: Thursday, September 29, 2011 2:35 AM
> To: Interoperability Documentation Help; pfif at tridgell.net; cifs-protocol at samba.org
> Subject: FRSRPC: questions about schedule
>
> Hello dochelp team,
>
> In ms-frs1.pdf we have at paragraph "3.3.2.1.1 SYSVOL Connection ScheduleTimer"
>
>   SYSVOL connection between sites. SYSVOL replication is initiated between two inter-site members at the start of the 15-minute interval, assuming the schedule is open. The connection MUST be using a trigger schedule. When a triggering schedule is used, the upstream partner ignores its schedule and responds to any request by the downstream partner. When the schedule closes, the upstream partner unjoins the connection only after the current contents of the outbound log, at the time of join, have been sent and acknowledged.
>
> Given the fact that, from my understanding, FRS is pushed based, what's the implication of this ?
> Because even if it's the downstream partner that is sending change notification it has to wait for the upstream to create a connection and once it's done it can start to send files.
>
> Also the unjoin command is send by the one who created the connection that is to say the downstream partner, so how can the upstream partner "unjoin" the connection ?
> Also can you clarify what's the meaning "when the schedule close" means exactly ? I understand that by default you have a schedule open every 15 minutes, but for how long it is open ?
>
>
> Thanks.
>
> Matthieu.
>
> --
> Matthieu Patou
> Samba Team
> http://samba.org
>
>
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-- 
Matthieu Patou
Samba Team
http://samba.org