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

Pascal Charest pascal.charest at labsphoenix.com
Thu Jul 28 21:36:39 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,

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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