[Samba] 答复: implement of persistent handle in SMB2.1

[Weidong]

hi Michael,

Sorry for taking so long to reply, I just get back on vacation. Your advice is very helpful.
Our purpose is no IO interrupted with Window 7 cifs client accessing the shared folder
when virtual IP taken over by another node. SMB3.0 or newer protocol do meet that demand,
but Window 7 cifs client only supports SMB2.1 protocol and previous versions. So we
need implement a persistent-handle-like feature base on SMB2.1.

Regards,
weidong

-----邮件原件-----
发件人: Michael Adam [mailto:obnox at samba.org]
发送时间: 2016年9月29日 19:18
收件人: weidong 12656 (RD)
抄送: samba at lists.samba.org
主题: Re: implement of persistent handle in SMB2.1

On 2016-09-28 at 12:50 +0000, Weidong wrote:
> hi Michael：

Hi Weidong,

Thank you for your message!

> We want to implement the ‘persistent handle’ function under Windows
> 7(SMB 2.1), which has only local ‘durable handle’.

Hmm. As you say: Windows 7 / SMB 2.1 does _not_ support presistent handles. This requires SMB 3.0 or newer.
Windows 7 supports durable handles, which is already supported in Samba.

> For now my plan is just to synchronize the following files between
> cluster nodes:
> smbXsrv_open_global.tdb.0
> smbXsrv_session_global.tdb.0
> smbXsrv_tcon_global.tdb.0
> locking.tdb.0
>
> It probably won’t be completed, so I’m writing to ask for your advice.
> Any help would be highly appreciated!

These databases are already distributes in the cluster by ctdb, as the .0 indicates! They are volatile and not persistent databases though.

In order to implement persistent handles properly, it is correct that we need to make some content of these DBs persistent, or at least more persistent than they are now, but it also requires some modifications in the smb code itself. For the latter, there are already poc patches circulating, and the real challenge is in fact the making-persistent of the db data (without loosing too much of performance).

But I still don't see how this relates to Windows7 / SMB 2.1.
Clarifications appreciated...

Cheers - Michael
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