Smart flash cache and Oracle Linux 6

I can't use smart flash cache feature on Oracle database 11.2.0.3.0 I installed on Oracle Linux 6.
I installed Oracle database 11.2.0.3.0 on Oracle Linux 6.1 and try to use smart flash cache feature,
I got this error when I start database:
ORA-00439: feature not enabled: Server Flash Cache
ORA-01078: failure in processing system parameters
My environment are:
OS: Oracle Linux 6.1 (x86_64)
Kernel: 2.6.32-100.34.1.el6uek.x86_64
DB: 11.2.0.3.0
Related parameter in pfile I used to start database to use smart flash cache feature,
*.db_flash_cache_file='/d09/db_flash_cache/db_flash_file.raw'
*.db_flash_cache_size=32G
I have accomplished this on Oracle database 11.2.0.2.0 on Oracle Linux 5.5 before, I don't think new version of database cause the issue but I'm not sure is there any smart flash cache issue with the Oracle Linux 6.1?
Note:
I need to use Oracle Linux 6.1 instead of Oracle Linux 6.2 and can't updated the kernel to UEK2 because the SSD PCI-E card only support on this distro and kernel version.
Edited by: Rapid E-Suite on Apr 16, 2012 11:22 AM

Hi;
Oracle Enterprise Linux was changed to Oracle Linux, isn't ?
Oracle stopped calling their Linux distro as "Oracle Enterprise Linux" since OEL5.5 or 5.6 (I'm not sure). Therefore, today there is Oracle Linux only? If so, I'm using OL6.1 also means OEL6.1, correct?
But, If the doc really means Oracle Enterprise Linux only then should it means OEL5.5 or 5.6?AFAIK both refer to Oracle Linux.If somebody mention they have OEL6.1 or Oracle linux 6.1 than I accept it Oracle linux(Enterprise)
You may see FAQ documents:
http://www.oracle.com/us/technologies/027617.pdf?ssSourceSiteId=ocomtr
If you have still dubt than I suggest rise thread at Forum Home » Linux » Oracle Linux forum part
Regard
Helios

Similar Messages

Database Smart Flash Cache and Data Guard

We are on Oracle 11.2.0.2 on OEL 5 and our considering buying fusion io (PCIe flash drives) for our Production (Primary) database.
My question is; Can we use Physical Data Guard with the Primary side using Database Smart Flash Cache and keep-ing tables and/or partitions in the Flash Cache and have a Standby side that does not have Database Smart Flash Cache?

Yes you can.
Data Guard will not check what type drive you are using. As long as you meet the database and network requirements it will work.
http://www.oracle.com/technetwork/database/features/availability/maa-090890.html
Check out these white papers if you have concerns
"Migration to Automatic Storage Management (ASM)"
"Best Practices for Creating a Low-Cost Storage Grid for Oracle Databases"
In addition here's an example of using two different file systems with Data Guard
http://pythianpang.wordpress.com/2009/07/07/data-guard-asm-primary-to-filesystem-physical-standby-using-rman-duplicate/
Best Regards
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Smart Flash Cache

Hi,
is the smart flash cache only available on sun oracle hardware ?
I know that this option is available only on OEL end Solaris, but I'n not sure on hardware ?
Thank a lot.

Hi;
Oracle Database Smart Flash Cache is a feature that was first introduced with Oracle Database 11g Release 2. Only available on Oracle Linux and Oracle Solaris, this feature increases the size of the database buffer cache without having to add RAM to the system. In effect, it acts as a second level cache on flash memory and will especially benefit read-intensive database applications.
Source:
http://blogs.oracle.com/linux/entry/oracle_database_smart_flash_cache_only_on_oracle_linux_and_oracle_solaris
Also see:
How To Size the Database Smart Flash Cache [ID 1317950.1]
Regard
Helios

Smart flash cache algorithm

I'd like to understand exactly how smart flash cache algorithm works.
I’ve read the Oracle white paper on smart flash cache. It says following:
Exadata Smart Flash Cache provides an automated caching mechanism for frequently-accessed data in the Exadata Database Machine.
What is the algorithm to figure out "frequently accessed data”?
It also say following -
The Oracle Database and Exadata Storage Server Software work closely together to cache frequently accessed data.
When the database sends a read or write request to Exadata Storage Server, it includes additional information in the request about whether the data is likely to be read again and therefore whether it should be cached.
Again what's the algorithm to figure out that data is likely to be read again?
Does it simply cache all random reads against tables and indexes and ignores all sequential reads, scans, writing backups and mirrored blocks?
I’ve also read that, Exadata tags each DB I/O is with metadata indicating I/O type which influence caching . Can somebody shed light on what are various I/O types and which ones are cached?

user12254641 wrote:
Thanks for your inputs.
I see it knows what not to cache.
However I was wondering if it has any special algorithm to decide frequently accessed data.
It seems it will cache all random read/writes and of course file headers and control files.There are really two parts to caching: 1) what to cache and 2) the management of cached data.
Assuming cell_flash_cache = default for these segments: index/table, any single block operation is cached. Also IIRC, multi-block reads (but not smart scan multi-block reads) are also cached, up until a certain size (64k or 128K are numbers that comes to mind, but I don't have the code open to check at this moment).
The cache management is basically LRU based, like the db buffer cache -- frequently accessed data is kept on the hot end, and data is aged out on the cold end and replaced.
While I'm sure "algorithms" are interesting for the geek in us, I 'm not sure how this info aids in any management or decision making. Questions are generally better formulated discussing what you would like to do so that appropriate advice can be given. You're question is context free.
Regards,
Greg Rahn | blog | twitter | linkedin

Pin redo logs into smart flash cache (Exadata Flash PCI F20 cache)

Need to know if we could pin redo logs into smart flash cache.
For example to pin table..
we use Alter table dhaval storage (cell_flash_cache keep) -----
Similarly can we pin redo logs into flash cache ?
If not, what is the alternative to put redo logs into flash cache ?

At Oracle OpenWorld the Exadata Smart Flash Log feature was announced. The Smart Flash Log feature requires Exadata Storage 11.2.2.4.0 or later, and Databases version 11.2.0.2 Bundle Patch 11 or greater. This feature allows a modest amount of flash to be used as a secondary write place. It wites redo to both flash and disk and returns the call to the db for the first one that finishes. By doing so it improves user transaction response time, and increases overall database throughput for IO intensive workloads.
Regards,
Greg Rahn
http://structureddata.org

Parameters of NFS in Solaris 10 and Oracle Linux 6 with ZFS Storage 7420 in cluster without database

Hello,
I have ZFS 7420 in cluster and OS Solaris 10 and Oracle Linux 6 without DB and I need mount share NFS in this OS and I do not know which parameters are the best for this.
Wich are the best parameters to mount share NFS in Solaris 10 or Oracle Linux 6?
Thanks
Best regards.

Hi Pascal,
My question is because when We mount share NFS in some servers for example Exadata Database Machine or Super Cluster for best performance we need mount this shares with specific parameters, for example.
Exadata
192.168.36.200:/export/dbname/backup1 /zfssa/dbname/backup1 nfs rw,bg,hard,nointr,rsize=131072,wsize=1048576,tcp,nfsvers=3,timeo=600 0 0
Super Cluster
sscsn1-stor:/export/ssc-shares/share1 - /export/share1 nfs - yes rw,bg,hard,nointr,rsize=131072,wsize=131072,proto=tcp,vers=3
Now,
My network is 10GBE
What happen with normal servers only with OS (Solaris and Linux)?
Which parameters I need use for best performance?
or are not necessary specific parameters.
Thanks.
Best regards.

Install questions on OVM Manager and Oracle Linux

I installed OVM Server 3.0.3 on a 64-bit server class box.
Getting tight with a spare box, I tried to install OVM Manager on the Oracle VirtualBox as a VM and also to install it on the top of OVM Server on the same hardware box but neither has been successful.
So, I'm thinking of rather installing OVM Manager on one of my laptops.
Before proceeding to wipe out the data on my laptop, I'd like to check couple of things:
1. I take it that the 32-bit OVM Manager should have no problem working with 64-bit OVM Server, correct?
2. The OVM Manager itself doesn't include with a bootable Linux image and should be installed on the top of a pre-installed Linux (e.g., Oracle Linux), so I need to install Oracle Linux first on my laptop and install OVM Manager on top of it, right?
Thanks for your help in advance!
- Young

user7259518 wrote:
1. I take it that the 32-bit OVM Manager should have no problem working with 64-bit OVM Server, correct?That's fine.
2. The OVM Manager itself doesn't include with a bootable Linux image and should be installed on the top of a pre-installed Linux (e.g., Oracle Linux), so I need to install Oracle Linux first on my laptop and install OVM Manager on top of it, right?Correct. You'll need at least 4GB of RAM for the Manager for a test/development environment, with 8GB+ recommended for Production, to cover both Oracle Database SE and Oracle WebLogic.

GUIDE: Oracle VM VirtualBox and Oracle Linux NIC bonding

Author: Dude
Date: 01-Jun-2013
Version: B
Last updates:
23-Jul-2013, changes required due to forum upgrade
The following is provided in the hope that it might be useful. If you wish to use it for the purpose of reference, presentation or education, please include the link or information to this forum posting. Thank you!
What is Linux network interface bonding? Simply put, the Linux system provides a kernel driver, which can create a logical network device (bond) using 2 or more Network Interface Controllers (NIC) to accomplish link-aggregation and adapter fault-tolerance. For more information, please see the Deployment Guide at https://linux.oracle.com/documentation/
The channel bonding interface supports several modes of operation. In a typical active-backup set up for fault-tolerance, the system performs MII-based health monitoring of the network interface slaves (eth0, eth1) and assigns them according to bond options and interface availability. In active-backup mode (mode 1), only the current active network device is seen externally.
Linux bonding for fault-tolerance under Oracle VM VirtualBox does not seem to function as advertised. Searching the Internet for more information shows that other people have tried to set up Linux bonding using various virtualization products, virtual host network adapter and bonding options, but without success.
It appears the management of Media Access Control addresses (MAC) interferes with internal routing methods between the host and the virtual machine guest. Using the modinfo bonding command (fig. 1) shows a listing of available parameters for the bonding kernel module. The fail_over_mac parameter addresses the Mac address issue in VirtualBox.
Fig.1
# modinfo bonding
filename:       /lib/modules/2.6.39-400.17.1.el6uek.x86_64
                /kernel/drivers/net/bonding/bonding.ko
parm:           fail_over_mac:For active-backup,
                do not set all slaves to the same MAC;
                0 for none (default), 1 for active, 2 for follow (charp)
Configuration Example
Virtualization Product: Oracle VM VirtualBox 4.2.10
VM Guest OS: Oracle Linux 6.4 (x64)
VM adapter settings: Bridged Adapter, Paravirtualized Network (virtio-net)
Adapter1 (eth0): 080027436617, en0, Ethernet 1
Adapter2 (eth1): 08002708F36A, en0, Ethernet 1
Note: If you wish to reset the network adapter names and MAC addresses used by the Oracle Linux guest system, erase the content of /etc/udev/rules.d/70-persistent-net.rules and restart the virtual machine.
1. Create or modify the following configuration files:
/etc/modprobe.d/bonding-eth0_eth1.conf
alias bond0 bonding
/etc/sysconfig/network-scripts/ifcfg-bond0
DEVICE=bond0
IPADDR=10.0.2.12
NETMASK=255.0.0.0
GATEWAY=10.0.0.138
DNS1=10.0.0.138
DNS2=8.8.8.8
ONBOOT=yes
BOOTPROTO=none
USERCTL=no
BONDING_OPTS="mode=1 miimon=100 fail_over_mac=1"
/etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no
/etc/sysconfig/network-scripts/ifcfg-eth1
DEVICE=eth1
BOOTPROTO=none
ONBOOT=yes
MASTER=bond0
SLAVE=yes
USERCTL=no
2. Restart the system or network services (root):
Fig. 2
# service network restart
Configuration Test
Enter the following commands as user root to verify proper operation of NIC bonding:
Fig. 3
# tail /var/log/messages
bond0: setting mode to active-backup (1).
bond0: Setting MII monitoring interval to 100.
bond0: Setting fail_over_mac to active (1).
bond0: Adding slave eth0.
bond0: making interface eth0 the new active one.
bond0: first active interface up!
bond0: enslaving eth0 as an active interface with an up link.
bond0: Adding slave eth1.
bond0: enslaving eth1 as a backup interface with an up link.
Fig. 4
# ifconfig
bond0     Link encap:Ethernet HWaddr 08:00:27:43:66:17
          inet addr:10.0.2.12 Bcast:10.255.255.255 Mask:255.0.0.0
          inet6 addr: fe80::a00:27ff:fe43:6617/64 Scope:Link
          UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
eth0      Link encap:Ethernet HWaddr 08:00:27:43:66:17
          UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
eth1      Link encap:Ethernet HWaddr 08:00:27:08:F3:6A
          UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
Fig. 5
# netstat -rn
Kernel IP routing table
Destination     Gateway         Genmask         Flags   MSS Window irtt Iface
0.0.0.0         10.0.0.138      0.0.0.0         UG        0 0          0 bond0
10.0.0.0        0.0.0.0         255.0.0.0       U         0 0          0 bond0
169.254.0.0     0.0.0.0         255.255.0.0     U         0 0          0 bond0
Fig. 6
# ifconfig eth0 down
# tail /var/log/messages
bond0: link status definitely down for interface eth0, disabling it
bond0: making interface eth1 the new active one.
# ifconfig
bond0     Link encap:Ethernet HWaddr 08:00:27:08:F3:6A
          inet addr:10.0.2.12 Bcast:10.255.255.255 Mask:255.0.0.0
          inet6 addr: fe80::a00:27ff:fe43:6617/64 Scope:Link
          UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
eth1      Link encap:Ethernet HWaddr 08:00:27:08:F3:6A
          UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
Fig. 7
# ifconfig eth0 up
# ifconfig eth1 down
# tail /var/log/messages
bond0: link status definitely up for interface eth0, 4294967295 Mbps full duplex.
bond0: link status definitely down for interface eth1, disabling it
bond0: making interface eth0 the new active one.
# ifconfig
bond0     Link encap:Ethernet HWaddr 08:00:27:43:66:17
          inet addr:10.0.2.12 Bcast:10.255.255.255 Mask:255.0.0.0
          inet6 addr: fe80::a00:27ff:fe43:6617/64 Scope:Link
          UP BROADCAST RUNNING MASTER MULTICAST MTU:1500 Metric:1
eth0      Link encap:Ethernet HWaddr 08:00:27:43:66:17
          UP BROADCAST RUNNING SLAVE MULTICAST MTU:1500 Metric:1
During the above test, the client network connection from host 10.0.0.1 (ssh) was maintained without any noticeable interruption. As it can be seen from the syslog and ifconfig command output, the bond0 interface was automatically assigned either the MAC address of eth0 or eth1 and the fail-over worked as advertised.
Good luck!

Please see these docs/links.
Using Oracle VM with Oracle E-Business Suite Release 11i or Release 12 [ID 465915.1]
Certified Software on Oracle VM [ID 464754.1]
Oracle VM Templates -- Oracle E-Business Suite 12.1.3 (32-bit), Oracle E-Business Suite 12.1.1 (64-bit and 32-bit) and Oracle E-Business Suite Release 12.X Sparse Middle Tier (32-bit)
http://www.oracle.com/technetwork/server-storage/vm/ebs-093153.html
E-Business Suite 12.1.3 Templates for Oracle VM Now Available
http://blogs.oracle.com/stevenChan/2010/11/ebs1213_oraclevm.html
Live Migration of EBS Services Using Oracle VM
http://blogs.oracle.com/stevenChan/2010/01/ebs_live_migration_ovm.html
Using Oracle VM with Oracle E-Business Suite Virtualization Kit
http://blogs.oracle.com/stevenChan/2009/12/oracle_vm_ebs_virtualization_kit.html
New Oracle® VM Templates for Oracle Applications Now Available
http://www.oracle.com/us/corporate/press/068341
Very Cool! New Oracle VM Templates for Oracle E-Business Suite
http://blogs.oracle.com/virtualization/2010/11/very_cool_new_oracle_vm_templa.html
Thanks,
Hussein

Does OCI client result cache and oracle UCP work together?

I'm using Oracle 11.2.1.0. I've set up FCF and enabled OCI result cache on server side, so on client side, I'm using UCP for failover.
this is my datasource configuration:
<Resource name="jdbc/MyPool"
auth="Container"
factory="oracle.ucp.jdbc.PoolDataSourceImpl"
type="oracle.ucp.jdbc.PoolDataSource"
connectionFactoryClassName="oracle.jdbc.pool.OracleDataSource"
url="jdbc:oracle:oci:@dbhost:1521/myDb"
user="db_user"
password="db_password"
fastConnectionFailoverEnabled="true"
onsConfiguration=""
connectionPoolName="dbPool"
initialPoolSize="5"
minPoolSize="5"
maxPoolSize="25"
connectionWaitTimeout="10000"
inactiveConnectionTimeout="120000"
abandonConnectionTimeout="60"
validateConnectionOnBorrow="true"
sqlForValidateConnection="select user from dual"
maxStatements="30"/>
I've enabled OCI client result cache.
I use /*+ result_cache */ in my query to take advantage of the result cache.
so I execute the following scenario:
i) select /*+ result_cache */ value from myTable where id=1; (this returns a result.)
ii) update myTable to set a different value for id=1 record;
iii) run select query again; (this should return a different result. oci result cache gets updated when table changes.)
if I take out
"sqlForValidateConnection" and/or "validateConnectionOnBorrow" (i.e. disable sql validation on borrow), the 2nd query after table update doesn't show the latest result. it's still showing the old query result.
is this a bug? that UCP validation on borrow has an impact on OCI result cache function? this doesn't happen if using dbcp java connection pooling with OCI result cache.

it turns out I ran the test against an oracle server that doesnt have FCF configured, nor ONS.
once i switched to a correct oracle cluster, my test passed.

Flash Date and Oracle date

Is it possible to convert a date being retrieved from an
oracle database to the flash Date format in flash so that the
different Actionscript date functions can be applied to the
retrieved date.

Hello gents!
Like this. Conversion is pretty easy, when we need a readable
date we can usually concat one with the Date class methods
getMonth, getTime and so on. Creating flash dates is done the other
way around, by using setDate and the other methods of the Date
class.

11gR2 Vs Exadata- Flash Cache performance

Flash Cache feature is available in both 11gR2 & Exadata. The difference being in 11gR2 it is an extension of the database buffer, however in Exadata it is a separate hardware component in the storage server.
Apart from this, I would like to know how the Exadata Smart Flash Cache is superior to the 11gR2 flash cache? Is it that the 11gR2 flash cache is not "smart" and ends up caching data that is not useful in terms of caching.
The 11gR2 oracle documentation does not seem to mention anything about this flash cache feature. Any idea?
Edited by: museshad on Jun 8, 2011 2:13 PM

Exadata Smart Flash Cache and Database Smart Flash Cache use SSD advantages.
On Exadata, We don't need to change anything in Database (database machine). We just "create flashcache" on cell. and Exadata Environment not support 11gR2 feature (Database Smart Flash Cache), Because it has Exadata Smart Flash Cache.
http://surachartopun.com/2011/02/how-to-use-exadata-smart-flash-cache.html
On 11gR2 (none Exadata) and have flash disk, we can use Database Smart Flash Cache, We have to change 2 initialization parameters on database.
db_flash_cache_file
db_flash_cache_size
http://surachartopun.com/2010/02/oracle-11gr2-flash-cache.html
Flash Cache feature is available in both 11gR2 & Exadata. On Exadata, we use Exadata SMart Flash Cache.
On None Exadata, we use database smart flash cache.
*** Exadata Environment not support 11gR2 feature (Database Smart Flash Cache) ***
The difference being in 11gR2 it is an extension of the database buffer, however in Exadata it is a separate hardware component in the storage server.when we get data, we read from disks to database buffer, when blocks are evicted from database buffers, they are stored in flash cache. After that ... someone get data again -> oracle read in database buffer cache, if not found, then oracle read in flash cache(if not found, oracle read from disks)
read more:
http://www.oracle.com/technetwork/articles/systems-hardware-architecture/oracle-db-smart-flash-cache-175588.pdf
http://www.oracle.com/technetwork/middleware/bi-foundation/exadata-smart-flash-cache-twp-v5-1-128560.pdf
Apart from this, I would like to know how the Exadata Smart Flash Cache is superior to the 11gR2 flash cache? Is it that the 11gR2 flash cache is not "smart" and ends up caching data that is not useful in terms of caching.read 2 above whitepapers.

OEL and Oracle Flash Cache

Hi Im wanting to experiment with Oracle Flash Cache,
I was made aware the other day that I could only use this on OEL o/s
My Pc is currently installing this..
But could some one please clarify to me the next steps I need to take? ....
Do i next just install a standard version of 11g/r2 on OEL? .... then run the patch i believe there is to enable flash cache?
what is the oracle VM that is offered alongside the OEL O/S ?
Any help would be appriciated

Thanks, its just I was told on this forum and the following link also says:
http://guyharrison.squarespace.com/blog/2009/11/24/using-the-oracle-11gr2-database-flash-cache.html
that.... if I want to use Flash Cache and im running 11g/r2 on OEL .. then I need to install the following patch to allow this:
8974084:META BUG FOR FLASH CACHE 11.2PL BUGS TO BACKPORT TO 11.2.0.1 OEL
...Is this not true? Do i not actually need to install the patch? ... I simply install 11g/r2 and it will work?

11.2 Flash Cache feature

I an 11.2 RAC database running.
I tried to enable Flash Cache
db_flash_cache_file
db_flash_cache_size
when I tried to start the database i get these errors
ORA-00439: feature not enabled: Server Flash Cache
ORA-01078: failure in processing system parameters
Does anyone know how to enable the feature?
Daniel

i wonder if Oracle is using ordinary SSD in Exadata Storage Cell to enable the smart flash cache feature. Has anybody seen an Exadata V2 and can report if there are SATA/SAS - SSDs with an ordinary hard disk controller build into the storage cell or if they do it a somehow other way. All i have read is that these flash devices are not filled by a LRU algorithm. I am really interested in technical details.http://www.oracle.com/technology/products/bi/db/exadata/pdf/exadata-technical-whitepaper.pdf
Each Exadata cell comes with 384 GB of Exadata Smart Flash Cache. This solid state storage delivers dramatic performance advantages with Exadata storage. It provides a ten-fold improvement in response time for reads over regular disk; a hundred-fold improvement in IOPS for reads over regular disk; and is a less expensive higher capacity alternative to memory. Overall it delivers a ten-fold increase performing a blended average of read and write operations.
The Exadata Smart Flash Cache manages active data from regular disks in the Exadata cell – but it is not managed in a simple Least Recently Used (LRU) fashion. The Exadata Storage Server Software in cooperation with the Oracle Database keeps track of data access patterns and knows what and how to cache data and avoid polluting the cache. This functionality is all managed automatically and does not require manual tuning. If there are specific tables or indexes that are known to be key to the performance of a database application they can optionally be identified and pinned in cache.There look to be two important advantages over regular SSD attached to an Oracle database here: that the caching is in combination with the Oracle Database (not just LRU, just as you point out yourself), but also that the storage cell's SmartScan technology will only project the required rows and columns to the database server so that higher effective bandwidths are achieved.

Flash Cache is not Flash Disk. Right ?

Hardware: X3 - Half Rack
# imageinfo
Kernel version: 2.6.32-400.11.1.el5uek #1 SMP Thu Nov 22 03:29:09 PST 2012 x86_64
Image version: 11.2.3.2.1.130109
Image activated: 2013-09-24 18:12:52 +0800
Image status: success
System partition on device: /dev/mapper/VGExaDb-LVDbSys1
In our Non-Exadata RAC DBs we use LUNs from Hitachi VSP frame. For very busy DBs like Siebel , we wanted to place our Online Redo logs on high speed disks.
So, our Hitachi SAN admins have allocated LUNs exclusively from Flash Disks within Hitachi VSP frame and we have created Redo Log diskgroup based on these 'Thick provisioned' disks.
This has increased the performance of our RAC DBs significantly.
As I understand, In exadata, you don't have the normal flash disk. Instead, the flash modules are mounted in a PCIexpress card.
In CellCLI> list physicaldisk detail you can see multiple entries like below belonging to the 'flash disk'
          name:                   FLASH_1_0
         diskType:               FlashDisk
         luns:                   1_0
         makeModel:              "Sun Flash Accelerator F40 PCIe Card"
         physicalFirmware:       UI39
         physicalInsertTime:     2013-09-13T17:56:10+08:00
         physicalSerial:         5L0066Y5
         physicalSize:           93.13225793838501G
         slotNumber:             "PCI Slot: 1; FDOM: 0"
         status:                 normal
Although these flash cards can store persistent data because it has battery in it in server goes down, is it actually used to store persistent data.
Smart flash cache is just a caching mechanism for frequently accessed data. Right ? We cannot create diskgroups based on disks from these 'Flash Disks' . Right ?

Hi GaryB,
The short answer to your question is: yes, it's possible to use configure flash as permanent storage using "flash griddisks". But in the case of redo logs, it would actually make them perform slower.
The longer explanation: foreground redo writes (the "log file sync" wait event) are very latency sensitive, so it's important for write to be acknowledged as fast as possible. Flash is considerably faster than disk, but not nearly as fast as battery-backed RAM. And Exadata storage servers do have a RAM write cache on their disk controllers. So you will get the best foreground redo write performance from RAM cache write, except when the write cache is full, at which point redo writes need to wait on disk.
Since 11.2.2.4.0 was released in 2012, Exadata has the capability to write redo to _both_ RAM-cached disk and flash memory, and use whichever returns first. So you get the lightning-fast latency of RAM cache unless the cache is full, and worst-case latency is the speed of flash. This capability, smart flash logging, is enabled by default on new Exadata builds; you can check its status by running "view flashlog detail" in CellCLI.
More details in the official whitepaper: http://www.oracle.com/technetwork/database/exadata/exadata-smart-flash-cache-366203.pdf
Hope this helps!
Marc

Need RAC/ASM multinode flash cache configuration advice

We have a working two-node RAC database. We are installing a new 640gb fusion flash card in each node. The card is a double-card, so that it shows up as two devices: /dev/fioa and /dev/fiob on each node.
We have created two private disk groups, one on each node. The disk group on node 1 is "+FLASHCACHE" and the disk group on node 2 is "+FLASHCACHE2".
We haven't found any specific examples of how to configure the init parameters for flashcache on RAC/ASM. We are guessing that we should do the following. If someone would critique and confirm or suggest something different, we would appreciate it very much!
prod1.db_flash_cache_file='+FLASHCACHE/flash1'
prod2.dg_flash_cache_file='+FLASHCACHE2/flash2'
*.db_flash_cache_size=600G
Thanks for any advice.
Jim
Edited by: jimbev90 on Jan 5, 2012 8:18 AM

Hi Jim,
prod1.db_flash_cache_file='+FLASHCACHE/flash1'
prod2.dg_flash_cache_file='+FLASHCACHE2/flash2'
*.db_flash_cache_size=600GYour configuration is correct.
Database Smart Flash Cache is not shared across RAC nodes; it is private to each RAC instance. For that reason, each RAC instance must define its own local flash cache file path. When the flash cache is managed by ASM, a separate diskgroup is needed for the flash cache of each instance.
You can use ALTER SYSTEM to set db_flash_cache_size to zero to disable the flash cache. You can also use ALTER SYSTEM to set the flash cache back to its original size to reenable it.
Read this white paper Oracle Database Smart Flash Cache
http://www.oracle.com/technetwork/articles/systems-hardware-architecture/oracle-db-smart-flash-cache-175588.pdf
Regards,
Levi Pereira

Smart flash cache and Oracle Linux 6

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