[DRBD-user] Deleting directories/files from drbd drive getting hung for some time.

Balreddy Medipally balreddy.m at imimobile.com
Fri Jul 29 06:05:02 CEST 2011

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hi,

 

            Thank you for the reply; we are deleting MYISAM tables not
the INNODB tables.

 

And while dropping table I am able to copy files in DRBD drive.

 

Thanks,

BalReddy. 

________________________________

From: pascal.charest at gmail.com [mailto:pascal.charest at gmail.com] On
Behalf Of Pascal Charest
Sent: Friday, July 29, 2011 1:07 AM
To: Balreddy Medipally
Cc: Matt Graham; drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] Deleting directories/files from drbd drive
getting hung for some time.

 

Hi, 


 

Wild guess here: Would you be using INNODB engine for your >50gb tables,
with --innodb-file-per-tables option set to 'true' in /etc/my.cnf, and
some  high value for your buffers ? There are some creepy bugs in MySQL
that has no link with DRBD that would create such lockdown.

 

As a tangent question: are you able to copy a file to the file system
while you drop that table in MySQL ? 

 

P.

 

--
Pascal Charest, 
Cutting-edge technology consultant @ Les Laboratoires Phoenix
http://www.labsphoenix.com 



On Wed, Jul 27, 2011 at 12:07 AM, Balreddy Medipally
<balreddy.m at imimobile.com> wrote:

Hi Matt,

       I couldn't found anything like "sda: Uncorrectable error" in
dmesg and I am sure that there is no faulty HDD in our servers.
Actually we are using DRBD for MySQL high availability, so when dropping
some big table like 50GB or bigger than that applications are not able
to access MySQL DB time particular time.

 Below is my drbd.conf file.

# please have a a look at the example configuration file in
# /usr/share/doc/drbd/drbd.conf
#
resource drbd0 {
protocol C;
startup {
become-primary-on both;
}
net {
       timeout 60;
       max-epoch-size  8000;
       max-buffers     8000;
       unplug-watermark        128;
       connect-int     10;
       ping-int        10;
       sndbuf-size     1024k;
       ko-count        180;
       ping-timeout    5;
       allow-two-primaries;
       cram-hmac-alg sha256;
       shared-secret DRBDpassw0rd;
       after-sb-0pri discard-least-changes;
       after-sb-1pri violently-as0p;
       after-sb-2pri violently-as0p;
       rr-conflict violently;
}
syncer {
       rate 200M;
       al-extents 3389;
}
disk {
       no-disk-barrier;
       no-disk-flushes;
       no-md-flushes;
       on-io-error detach;
}

on DB-01 {
        device           /dev/drbd0;
        disk             /dev/cciss/c0d0p2;
        address          ipv4 192.168.169.3:7768;
        meta-disk        internal;
}
on DB-02 {
        device           /dev/drbd0;
        disk             /dev/cciss/c0d0p9;
        address          ipv4 192.168.169.4:7768;
        meta-disk        internal;
       }
}


Thanks,
Balreddy.


-----Original Message-----
From: drbd-user-bounces at lists.linbit.com
[mailto:drbd-user-bounces at lists.linbit.com] On Behalf Of Matt Graham
Sent: Tuesday, July 26, 2011 10:01 PM
To: drbd-user at lists.linbit.com
Subject: Re: [DRBD-user] Deleting directories/files from drbd drive

getting hung for some time.

From: "Balreddy Medipally" <balreddy.m at imimobile.com>
> We are using Protocol C in our drbd.conf file.  [When we are]
> deleting directories/files from drbd drive, [it's hanging up] for
> some time.  In this period of time it is not allowing us to do any
> operations on [the] drbd drive.

The first thing to do is to check the output from dmesg on both nodes
and make
sure you don't see anything like "sda: Uncorrectable error writing
sector
12345678".  If you see this, it means one of your disks is dying
horribly.
This can cause delays while writing, since the kernel and disk will try
to
write to that sector several times.

> Please let us know if there is any tuning to be done in drbd level.

It's impossible to tell, since we can't see your drbd.conf.  Put that
file on
your webspace somewhere, and follow up with a link.

--
Matt G / Dances With Crows
The Crow202 Blog:  http://crow202.org/wordpress/
There is no Darkness in Eternity/But only Light too dim for us to see

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