dump slow after upgrade to Centos5

Issues related to hardware problems

dump slow after upgrade to Centos5

Postby ToddAndMargo » 2007/10/09 01:00:26

Hi All,

When I upgraded from CentOS4.4 to CentOS 5, I totally
wiped my hard drive clean and started over fresh.

Problem, my dumps (dump and restore backup utility)
is 3.5 times slower under CentOS5 than under CentOS4.4.

Anyone have any tips/advice as to how to correct this?
Could there be something wrong with my hard drive that
makes for very slow reads? Anything?

Many thanks,
-T

under 4.4, 1:05 hours, approx 52 GB backup file
under 5.0, 3:16 hours, approx 43 GB backup file
ToddAndMargo
 
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Re: dump slow after upgrade to Centos5

Postby sub31 » 2007/10/09 15:43:30

Are you doing this backup to tape or to hdd?
I've the same problem and testing portions of 110G and around.
But I test this portions only on tapes, not on hdd.
I'll try it on hdd tomorow. Thanks.
sub31
 
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Re: dump slow after upgrade to Centos5

Postby ToddAndMargo » 2007/10/09 18:21:48

Hi Sub31,

The problem is no respector of HDD or tape drive. See
speed tests below.

Do to the 3.5x performance hit, I am afraid to use CentOS5 on
any of my new customer's servers.

Question: are you using a RAID card? If so, which one?

-T


The motherboards (3) are the Supermicro x7dal-e:

http://www.supermicro.com/products/moth ... 7DAL-E.cfm

The LSI Megaraid cards are the SATA-150-4 and SATA 300-4XLP:

http://www.lsi.com/storage_home/product ... index.html
http://www.lsi.com/storage_home/product ... index.html

The tape drive is a Exabyte VXA-3.
http://exabyte.com/products/products/ge ... rod_id=641
run from an Adaptec 19160 SCSI-U160 LVDS Controller

The backup hard drive is an external SATA drive (eSATA)


Computer A: VXA-3, CentOS 5 , SATA 300-4XLP

DUMP: 17815320 blocks (17397.77MB) on 1 volume(s)
DUMP: finished in 6473 seconds, throughput 2,752 kBytes/sec

DUMP: 5038380 blocks (4920.29MB) on 1 volume(s)
DUMP: finished in 1872 seconds, throughput 2,691 kBytes/sec
Note: 3 times slower than Computer B

Computer B: VXA-3, CentOS 4.5 , SATA-150-4

DUMP: 35933440 blocks (35091.25MB) on 1 volume(s)
DUMP: finished in 4396 seconds, throughput 8,174 kBytes/sec

DUMP: 27096640 blocks (26461.56MB) on 1 volume(s)
DUMP: finished in 3532 seconds, throughput 7,671 kBytes/sec


Computer C: eSATA, CentOS 4.4 & 5 , SATA-150-4

CentOS 4.4, 1:05 hours, approx 52 GB backup file 13,333 kBytes/sec
CentOS 5.0, 3:16 hours, approx 43 GB backup file 3,656 kBytes/sec
Note: 3.6 times slower


Computer C: misc speed tests

cp winxp.hdd /dev/null (7.7 GB), HDD=LSI, Cent 5: 1:44 min, Cent OS 4.4: 1:43 min
cp estat.hdd /dev/null (7.7 GB), HDD=eSata, Cent 5: 3:08 min, Cent OS 4.4: 3:07 min

cp winxp.hdd eraseme (7.7 GB), HDD=LSI, Cent 5: 4:50 min, Cent OS 4.4: 4:48 min
cp estat.hdd eraseme (7.7 GB), HDD=eSata, Cent 5: 7:22 min, Cent OS 4.4: 6:54 min

Parallels' start up of winxp, HDD=LSI, 44 sec
startup of Acrobat 8 Pro: 1st time: 5 sec; 2nd time: 2 sec

Parallels' start up of eSata, HDD=eSata, 38 sec
startup of Acrobat 8 Pro: 1st time: 7 sec; 2nd time: 1 sec
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Re: dump slow after upgrade to Centos5

Postby sub31 » 2007/10/10 13:13:53

Excuse me.
RAID Card for what?

Computer is
MB Tyan S2892
2x3ware9508 Raid Controlles 16x300Gb SATA drives.
1xAIC7902W onboard controller for connect external SCSI devices.
2xAXUS Brownie BR1600U3P SCSI Ultra 160 device with 16x250Gb IDE drives in each.
1xHP Storage Works Ultrium 460 LTO-2 Tape drive
1xQuantum LTO-2 Tape Drive
1xHP Storage Works Ultrium 920 LTO-3 Tape drive

For backup we are use tapes in these Tape drives.

As you can see this configuration use RAID massives but not all of them on RAID cards. Some of these RAIDs are on the RAID Storages.

Now I cannot represent adequate information about slower but can write some data for analises.
We write on tape different information in few sessions and this count is different but we can see from logs time of start, count of sessions, size of total writed data.
RHEL3:
Start - End : Size : Sessions
2007/07/23-13:07:01 - 2007/07/23-16:40:30 : 115.737 GB. : 5
2007/07/23-13:07:36 - 2007/07/23-16:52:54 : 163.738 GB. : 8
2007/07/25-09:50:42 - 2007/07/25-12:26:21 : 190.159 GB. : 8
2007/07/27-09:20:40 - 2007/07/27-10:44:21 : 115.603 GB. : 7
2007/07/30-09:49:18 - 2007/07/30-12:10:03 : 182.304 GB. : 10
CentOS 5:
2007/10/05-16:16:06 - 2007/10/06-16:32:30 : 98.534 GB. : 4
2007/10/05-16:26:00 - 2007/10/08-16:37:49 : 100.837 GB. : 2
2007/10/08-16:34:40 - 2007/10/09-17:12:23 : 176.883 GB. : 9
2007/10/08-16:41:36 - 2007/10/09-05:17:06 : 100.837 GB. : 4
2007/10/09-16:48:48 - 2007/10/09-22:22:14 : 73.3732 GB. : 4
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Re: dump slow after upgrade to Centos5

Postby ToddAndMargo » 2007/10/10 18:13:17

"Excuse me.
RAID Card for what?"

I was looking to see if the drivers for a common RAID
card might be the problem. Since we use different
cards, it is not the problem. (It was a long shot.)

We don't even use the same chipsets.

The only thing I see in common is our RAID cards are
installed in the PCI-X slot.

And, we both use motherboards with multiple I/O
slots (PCI-X, PCI, PCI-e).

Question: are you slow in other areas as well?
(I am 3 times slower in other areas as well.)

-T
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Re: dump slow after upgrade to Centos5

Postby ToddAndMargo » 2007/10/10 18:35:52

ToddAndMargo
 
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Re: dump slow after upgrade to Centos5

Postby sub31 » 2007/10/19 07:57:40

I use integrated scsi controller for external storages and for tape drives.
External storage have internal card with processor and memory for RAID functionality.
Now I try to use old dump utility on CentOS5.
I've the same result.
ATOP utility show me backing up device is 100% busy.
I think this problem not in dump utility. May be this problem in scsi drivers.
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Re: dump slow after upgrade to Centos5

Postby ToddAndMargo » 2007/11/04 22:06:38

Hi All,

Did some test from my install CD/DVD's in "rescue mode"
and the System Rescue CD from http://www.sysresccd.org
on Computer C. I used the same backup script (dump) that
I use in normal boot mode. I stopped the backup
after dump gave the first estimate of time:

"dump" CentOS5 install DVD in rescue mode:
transfer rate 4422 KB/s, estimated finish 4:10

"dump" CentOS4.4 (Kernel 2.6.9-42.EL) install CD in rescue mode:
transfer rate 8468 KB/s, estimated finish 2:09

"dump" System Rescue CD (Kernel 2.6.22.9):
transfer rate 4370 KB/s, estimated finish 4:15

This proves that the problem is not confined to CentOS5

-T
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Re: dump slow after upgrade to Centos5

Postby ToddAndMargo » 2008/01/06 05:40:08

Hi All,

Good news to report:

I put the following into my rc.local (other things are
miserably slow too, such as my virtual machine):


# Modify default IOSCHED to speed dump and virtual box up
# Under Kernel 2.6.18-53.1.4.el5-i686, the default is
# CONFIG_DEFAULT_IOSCHED="cfq"
echo "anticipatory" > /sys/block/sda/queue/scheduler


and ran a test backup:

DUMP: 4.67% done at 14315 kB/s, finished in 1:41

Under "cfq", it would be ~ 5:30. YIPEE!!!!!!!

For reference as to why I did such, please see:

http://bugzilla.kernel.org/show_bug.cgi?id=8636#c46

OH HAPPY CAMPING HAS RETURNED!
-T
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Re: dump slow after upgrade to Centos5

Postby yyagol » 2008/01/06 06:20:11

Very interesting stuff .... thanks for the update , i know there was something wrong ,
may this be the reason why CentOS 5 is slower in general ?
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