[Ocfs2-users] OCFS2 strage freezes

[Yuri Kirsanov]

Thank you very much for your help!

I believe ocfs2 will be very good for my purposes.

----- Original Message ----- 
From: "Sunil Mushran" <Sunil.Mushran at oracle.com>
To: "Yuri Kirsanov" <flash at preferance.ru>
Cc: <ocfs2-users at oss.oracle.com>
Sent: Tuesday, March 04, 2008 9:50 PM
Subject: Re: [Ocfs2-users] OCFS2 strage freezes


> No delay in read as we won't have to flush those pages to disk.
> 
> Yuri Kirsanov wrote:
>> Yes, now I see it, thank you very much. So, it happends only when a 
>> large amount of data has to be flushed to disk on target system, right?
>>
>> Then, if I already have big file and just reading it from server, 
>> there will be no delays in access from two nodes, right?
>>
>> ----- Original Message ----- From: "Sunil Mushran" 
>> <Sunil.Mushran at oracle.com>
>> To: "Yuri Kirsanov" <flash at preferance.ru>
>> Cc: <ocfs2-users at oss.oracle.com>
>> Sent: Tuesday, March 04, 2008 9:28 PM
>> Subject: Re: [Ocfs2-users] OCFS2 strage freezes
>>
>>
>>> stat-ing a file makes the fs acquire a readlock (PR) forcing the 
>>> other node
>>> to downgrade from writelock (EX) which then forces it to flush the 
>>> dirty pages
>>> to disk. Say you have 500M to flush and your iscsi setup's io thruput 
>>> is 30MB/s.
>>> That'll be 16 secs.
>>>
>>> Note: The nodes are not frozen. The ls and cp processes are waiting 
>>> on the
>>> pages to flush to disk.
>>>
>>> You can confirm this by repeating the test and doing a "find ." 
>>> instead of ls.
>>> The former will not stat the file (will only stat the directory) and 
>>> thus avoid
>>> the force flush seen above.
>>>
>>> Yuri Kirsanov wrote:
>>>> Good day, everyone.
>>>>
>>>> I have SAN server build with Openfiler OS, with iSCSI mode turned 
>>>> on. I have two nodes, which connect to that server via iSCSI, using 
>>>> one of two active iSCSI partitions. I've installed ocfs2 1.3.3 with 
>>>> kernel 2.6.23.1, configured it, made ocfs2 partition and was 
>>>> successful in mounting it on both nodes. Everything works just fine, 
>>>> I can upload file from one node and delete it using another one, 
>>>> except for one strange thing. When I'm using ocfs2 mounted partition 
>>>> from one node, for example, uploading 1Gb test file into it, and I 
>>>> try to access that partition from another node - just to read 
>>>> directory, for example, - both nodes "freeze" for about 15-20 
>>>> seconds, both operations just stops for a while, and then copying 
>>>> continues on first node, while second one gets directory listing.
>>>>
>>>> I have no errors on both nodes, neither iSCSI ones, no ocfs2. All 
>>>> three servers are joined together using 1Gbit/sec network switch and 
>>>> there's no other machines on that switch.
>>>>
>>>> If you need any information, please feel free to ask me about it. 
>>>> Thanks in advance!
>>>>
>>>> _______________________________________________
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>>>> Ocfs2-users at oss.oracle.com
>>>> http://oss.oracle.com/mailman/listinfo/ocfs2-users
>>>>
>>>
>>>
>>
> 
>