….dell.com/pipermail/linux-poweredge/2012-June/046470.html transparent learn cycle NOTE: Virtual disks stays in Write Back mode, if enabled, during transparent learn cycle. When the TLC completes, the controller sets the next… The time frame for completion of a learn cycle is a function of the battery charge capacity and the discharge and charge…
Comment: Looking for RAID Controller without Battery Learning problems ?
April 26, 2013 By 11 Comments
Post: Looking for RAID Controller without Battery Learning problems ?
January 5, 2012 By 11 Comments
A lot have been written about Battery Learning Cycle problems and its impact to MySQL Performance. Here are … this PDF ZMCP (Zero-Maintenance Cache Protection) does not use battery but instead Capacitor plus flash. Capacitor provides enough energy for… supplied Flash module. This solution helps not only with battery discharge/learn cycle many Battery Backup Unit (BBU) based controllers help but also…
Post: Battery Learning still problem many years after
February 10, 2011 By 7 Comments
The performance problems caused by battery auto learning go many years back. We wrote about it, other people … see for how long battery cache gets disabled in your system (it is only part of all learn phase). You can also… write back even with no battery which will likely trash your database if power goes down during learning process. It may be…
Post: The perils of uniform hardware and RAID auto-learn cycles
November 16, 2010 By 16 Comments
… quickly on one of the failing machines. The result: the battery-backed cache was in write-through mode instead of write…. Same thing — write-through, battery charging. And the battery backup unit was set to run through auto-learn cycles periodically, which is generally… file and found the command we needed to disable auto-learn, (++text files and saving links to reference material), sent that…
Post: RAID System performance surprises
March 5, 2008 By 7 Comments
… be aware of couple of things Battery Learning and Charging Build in Battery has to pass through learning cycle every 3 months or so and this cycle takes about 7 hours according to the docs. During this time battery… enough for consistency check and patrol read but not for battery backed up cache being temporary disabled. Another thing you can…
Comment: Looking for RAID Controller without Battery Learning problems ?
January 5, 2012 By 11 Comments
…. And I do like not having to worry about the battery learn cycles our Dell/Lsi controllers are excellent at wrecking us… controllers as you can get all the info you need (battery/ZMM, individual disks, overal health, cache mode, rebuild progress, etc…
Post: More on dangers of the caches
September 23, 2010 By 5 Comments
… activity. It may be RAID writeback cache disabled due to battery learning but there must be something. This is actually where Trending… can serve all traffic without problems. So what we can learn from this, besides cache design related issues I mentioned in…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 9 Comments
… the problem. Many RAID controllers have to periodically go through battery learning cycle which switches RAID cache in write-through mode which…
Comment: The perils of uniform hardware and RAID auto-learn cycles
November 16, 2010 By 16 Comments
I have LSI controllers with BBU on workstation based pcs and the battery learn cycle is very annoying. But honestly never thought to tie it in with mysql/server performance. Thanks for this article.
Comment: RAID System performance surprises
March 5, 2008 By 7 Comments
… the command which tells when next Learn cycle to be: [root@DB01 ~]# omreport storage battery controller=0 Battery 0 on Controller PERC 5… : Battery 0 State : Ready Recharge Count : Not Applicable Max Recharge Count : Not Applicable Predicted Capacity Status : Ready Learn State : Idle Next Learn Time…
