2:44 a.m.
Hi,
I found some "dd" operations were launched contiguously in my vdsm.log.
Is this harmful? How was this operation caused?
From vdsm.log:
Dummy-51000::DEBUG::2012-10-11
15:38:57,243::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:38:57,305::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0388821 s, 26.3 MB/s\n'; <rc> = 0
Dummy-51000::DEBUG::2012-10-11
15:38:59,313::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:38:59,375::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0398412 s, 25.7 MB/s\n'; <rc> = 0
Dummy-51000::DEBUG::2012-10-11
15:39:01,383::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:39:01,445::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0393934 s, 26.0 MB/s\n'; <rc> = 0
Dummy-51000::DEBUG::2012-10-11
15:39:03,453::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:39:03,515::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0391104 s, 26.2 MB/s\n'; <rc> = 0
--
---
舒明 Shu Ming
Open Virtualization Engineerning; CSTL, IBM Corp.
Tel: 86-10-82451626 Tieline: 9051626 E-mail: shuming(a)cn.ibm.com or
shuming(a)linux.vnet.ibm.com
Address: 3/F Ring Building, ZhongGuanCun Software Park, Haidian District, Beijing 100193,
PRC
5:54 a.m.
On Thu, Oct 11, 2012 at 03:44:25PM +0800, Shu Ming wrote:
Hi,
I found some "dd" operations were launched contiguously in my vdsm.log.
Is this harmful? How was this operation caused?
That's storage.storage_mailbox.SPM_MailMonitor, polling for lvextend
requests. dd is used, since in the old days, vdsm did not have
storage.fileUtils.DirectFile.
The behavior is expected, but I cannot say that it is harmless.
The mailbox should be high on
http://wiki.ovirt.org/wiki/Vdsm_TODO#refactoring
since forking so much is a waste, as well as using strings instead of
bytearrays. Making the module as a separate, testable entity, is important,
too.
From vdsm.log:
Dummy-51000::DEBUG::2012-10-11
15:38:57,243::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
10:38 a.m.
After reading the code, every mailbox should be 4096 byte size.
And the total mailbox size is host * 4096. Ony one host is here, so
the total mailbox size here is 4096. why should the 'dd' operation
read 1024000 byte which is 1000K byte much lager than 4096 here?
2012-10-11 18:54, Dan Kenigsberg:
On Thu, Oct 11, 2012 at 03:44:25PM +0800, Shu Ming wrote:
> Hi,
>
> I found some "dd" operations were launched contiguously in my vdsm.log.
> Is this harmful? How was this operation caused?
That's storage.storage_mailbox.SPM_MailMonitor, polling for lvextend
requests. dd is used, since in the old days, vdsm did not have
storage.fileUtils.DirectFile.
The behavior is expected, but I cannot say that it is harmless.
The mailbox should be high on
http://wiki.ovirt.org/wiki/Vdsm_TODO#refactoring
since forking so much is a waste, as well as using strings instead of
bytearrays. Making the module as a separate, testable entity, is important,
too.
> From vdsm.log:
>
> Dummy-51000::DEBUG::2012-10-11
> 15:38:57,243::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
> if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
> iflag=direct,fullblock count=1 bs=1024000' (cwd None)
--
---
舒明 Shu Ming
Open Virtualization Engineerning; CSTL, IBM Corp.
Tel: 86-10-82451626 Tieline: 9051626 E-mail: shuming(a)cn.ibm.com or
shuming(a)linux.vnet.ibm.com
Address: 3/F Ring Building, ZhongGuanCun Software Park, Haidian District, Beijing 100193,
PRC
4:15 p.m.
On Thu, Oct 11, 2012 at 11:38:19PM +0800, Shu Ming wrote:
After reading the code, every mailbox should be 4096 byte size.
And the total mailbox size is host * 4096. Ony one host is here, so
the total mailbox size here is 4096. why should the 'dd' operation
read 1024000 byte which is 1000K byte much lager than 4096 here?
The controlling parameter is MAX_HOST_ID=250, not the number of current
cluster members.
5:59 a.m.
On 10/11/2012 09:44 AM, Shu Ming wrote:
Hi,
I found some "dd" operations were launched contiguously in my vdsm.log.
Is this harmful? How was this operation caused?
dd is the way vdsm reads and writes data in its metadata luns of a
storage domain.
Each storage domain (except for nfs-based storage domains) has several
special luns for managing the storage domain operations, one of them is
the inbox which is used for communication between hosts about storage
domains write operations that should executed by the SPM host etc.
The only thing I'm not happy with is the usage of 'dd' instead of
'/bin/dd'.
From vdsm.log:
Dummy-51000::DEBUG::2012-10-11
15:38:57,243::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:38:57,305::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0388821 s, 26.3 MB/s\n'; <rc> = 0
Dummy-51000::DEBUG::2012-10-11
15:38:59,313::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:38:59,375::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0398412 s, 25.7 MB/s\n'; <rc> = 0
Dummy-51000::DEBUG::2012-10-11
15:39:01,383::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:39:01,445::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0393934 s, 26.0 MB/s\n'; <rc> = 0
Dummy-51000::DEBUG::2012-10-11
15:39:03,453::__init__::1249::Storage.Misc.excCmd::(_log) 'dd
if=/rhev/data-center/6f6d4801-7447-48ea-b516-627d83e7801e/mastersd/dom_md/inbox
iflag=direct,fullblock count=1 bs=1024000' (cwd None)
Dummy-51000::DEBUG::2012-10-11
15:39:03,515::__init__::1249::Storage.Misc.excCmd::(_log) SUCCESS: <err>
= '1+0 records in\n1+0 records out\n1024000 bytes (1.0 MB) copied,
0.0391104 s, 26.2 MB/s\n'; <rc> = 0
--
Thanks,
Rami Vaknin, QE @ Red Hat, TLV, IL.
4221
days inactive
4223
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4 comments
3 participants
participants (3)
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Dan Kenigsberg -
Rami Vaknin -
Shu Ming