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

[Balreddy Medipally]

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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