# Enable Flashcache in 5.5 **URL:** \ **Category:** Other MySQL® Questions\ **Created:** [January 18, 2012, 6:46am UTC](https://forums.percona.com/t/enable-flashcache-in-5-5/1735 "2012-01-18T06:46:17Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![bigbluechief](https://avatars.discourse-cdn.com/v4/letter/b/ee59a6/32.png) [@bigbluechief](https://forums.percona.com/u/bigbluechief)\ **Post date:** [January 18, 2012, 6:46am UTC](https://forums.percona.com/t/enable-flashcache-in-5-5/1735/1 "2012-01-18T06:46:17Z")
I’m running multiple servers with Percona/MySQL 5.1.16 and Flashcache, which works quite fine. I’m now however having problems installing Percona/MySQL 5.5.19 on new servers with Flashcache, as the startup states there is a problem with the “Flashcache bypass”. Output from a server running 5.5.19: 120118 03:51:25 mysqld\_safe Starting mysqld daemon with databases from /var/lib/mysql120118 3:51:25 [Note] Flashcache bypass: disabled120118 3:51:25 [Note] Flashcache setup error is : ioctl failed120118 3:51:25 [Note] Plugin ‘FEDERATED’ is disabled.120118 3:51:25 InnoDB: The InnoDB memory heap is disabled120118 3:51:25 InnoDB: Mutexes and rw\_locks use GCC atomic builtins120118 3:51:25 InnoDB: Compressed tables use zlib 1.2.3120118 3:51:25 InnoDB: Using Linux native AIO120118 3:51:25 InnoDB: Initializing buffer pool, size = 120.0G120118 3:51:31 InnoDB: Completed initialization of buffer pool120118 3:51:31 InnoDB: highest supported file format is Barracuda.120118 3:51:36 InnoDB: Waiting for the background threads to start120118 3:51:37 Percona XtraDB ([http://www.percona.com](http://www.percona.com)) 1.1.8-rel24.0 started; log sequence number 324537592488120118 3:51:37 [Note] Slave SQL thread initialized, starting replication in log ‘mysql-bin.000104’ at position 74933008, relay log ‘/database/dblogs/mysql-relay-bin.000272’ position: 67383397120118 3:51:37 [Note] Event Scheduler: Loaded 0 events120118 3:51:37 [Note] /usr/sbin/mysqld: ready for connections.Version: ‘5.5.19-55-log’ socket: ‘/var/lib/mysql/mysql.sock’ port: 3306 Percona Server (GPL), Release rel24.0, Revision 204 If I however downgrade to Percona/MySQL 5.1.16 on the same server Flashcache works: 120118 05:48:12 mysqld\_safe Starting mysqld daemon with databases from /var/lib/mysql120118 5:48:12 [Note] Flashcache bypass: enabled120118 5:48:12 [Note] Plugin ‘FEDERATED’ is disabled.InnoDB: The InnoDB memory heap is disabledInnoDB: Mutexes and rw\_locks use GCC atomic builtinsInnoDB: Compressed tables use zlib 1.2.3120118 5:48:12 InnoDB: Initializing buffer pool, size = 120.0G120118 5:48:17 InnoDB: Completed initialization of buffer pool120118 5:48:17 InnoDB: highest supported file format is Barracuda.120118 5:48:22 Percona XtraDB ([http://www.percona.com](http://www.percona.com)) 1.0.17-rel13.1 started; log sequence number 45356120118 5:48:22 [Note] Event Scheduler: Loaded 0 events120118 5:48:22 [Note] /usr/sbin/mysqld: ready for connections.Version: ‘5.1.60-rel13.1-log’ socket: ‘/var/lib/mysql/mysql.sock’ port: 3306 Percona Server (GPL), 13.1, Revision 413 Flashcache is mounted on /var/lib/mysql. Is there a problem with Flashcache in Percona/MySQL 5.5, or does it wrongfully report that Flashcache bypass can’t be enabled? Is there any way for me to validate that MySQL works correctly, besides seeing that our SSD harddrives work as expected? ---
**Author:** ![freebsdsa](https://avatars.discourse-cdn.com/v4/letter/f/ebca7d/32.png) [@freebsdsa](https://forums.percona.com/u/freebsdsa)\ **Post date:** [February 10, 2012, 4:06pm UTC](https://forums.percona.com/t/enable-flashcache-in-5-5/1735/2 "2012-02-10T16:06:09Z")
I see the exact same thing with Percona 5.5.20 also. It would be nice to find out how to resolve this with out having to run 5.1. ---
**Author:** ![xaprb](https://avatars.discourse-cdn.com/v4/letter/x/49beb7/32.png) [@xaprb](https://forums.percona.com/u/xaprb)\ **Post date:** [February 17, 2012, 3:46pm UTC](https://forums.percona.com/t/enable-flashcache-in-5-5/1735/3 "2012-02-17T15:46:41Z")
I see no one else has responded and frankly I’m not sure – I’m not the expert in administering Flashcache. So you’re likely to get best results by engaging us for consulting. ---
**Author:** ![interrupted](https://avatars.discourse-cdn.com/v4/letter/i/3ab097/32.png) [@interrupted](https://forums.percona.com/u/interrupted)\ **Post date:** [April 16, 2012, 6:24pm UTC](https://forums.percona.com/t/enable-flashcache-in-5-5/1735/4 "2012-04-16T18:24:50Z")
got the same problem with 5.5.17+ anyone found a solution for this except downgrading to 5.1? ---
**Author:** ![interrupted](https://avatars.discourse-cdn.com/v4/letter/i/3ab097/32.png) [@interrupted](https://forums.percona.com/u/interrupted)\ **Post date:** [April 16, 2012, 7:18pm UTC](https://forums.percona.com/t/enable-flashcache-in-5-5/1735/5 "2012-04-16T19:18:17Z")
found something here: [URL][https://bugs.launchpad.net/percona-server/+bug/747032[/URL]](https://bugs.launchpad.net/percona-server/+bug/747032%5B/URL%5D) adding cd $datapath into /etc/init.d/mysql fixes this problem. cheers, Juergen ---
**Author:** ![seeekr](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@seeekr](https://forums.percona.com/u/seeekr)\ **Post date:** [April 19, 2012, 7:06am UTC](https://forums.percona.com/t/enable-flashcache-in-5-5/1735/6 "2012-04-19T07:06:36Z")
Hi Juergen, where exactly did you add that line in order to fix the issue? I’ve tried to add it, too, but the issue persists. (Please post the precise snippet!) Thanks! - Denis