[Ocfs2-users] OCFS2 strage freezes

[Sunil Mushran]

Oops... forgot to add. You can also avoid this by mounting the
volume with data=writeback. It is this default ordered journaling
mode (data=ordered) that is eventually forcing this data flush.

Sunil Mushran wrote:
> 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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>
>
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