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Transcript of RAC Best Practices on Linux Kirk McGowan Technical Director – RAC Pack Server Technologies Oracle...
RAC Best Practices on Linux
Kirk McGowanTechnical Director – RAC Pack
Server Technologies
Oracle Corporation
Session id: 40136
Roland KnappPrincipal Member Technical Staff – RAC Pack
Server Technologies
Oracle Corporation
Agenda Planning Best Practices
– Architecture– Expectation setting– Objectives and success criteria– Project plan
Implementation Best Practices– Infrastructure considerations– Installation/configuration– Database creation– Application considerations
Operational Best Practices– Backup & Recovery– Performance Monitoring and Tuning– Production Migration
Planning
Understand the Architecture– Cluster terminology– Functional basics
HA by eliminating node & Oracle as SPOFs Scalability by making additional processing capacity
available incrementally– Hardware components
Private interconnect/network switch Shared storage/concurrent access/storage switch
– Software components OS, Cluster Manager, DBMS/RAC, Application Differences between cluster managers
RAC Hardware Architecture
ClusteredDatabase
Servers
Mirrored Disk Subsystem
High Speed Switch or
Interconnect
Hub or Switch Fabric
NetworkCentralized Management
Console
Storage Area Network
Low Latency Interconnectie. VIA or Proprietary
Users
No SinglePoint Of Failure
Shared CacheShared Cache
RAC Software Architecture
Shared Disk DatabaseShared Disk Database
Shared Memory/Global Area
shared shared SQLSQL
log log bufferbuffer
. . .. . .Shared Memory/Global Area
shared shared SQLSQL
log log bufferbuffer
Shared Memory/Global Area
shared shared SQLSQL
log log bufferbuffer
Shared Memory/Global Area
shared shared SQLSQL
log log bufferbuffer
GES&GCSGES&GCS GES&GCSGES&GCS GES&GCSGES&GCS GES&GCSGES&GCS
Shared Data Model
RAC on Linux HW & SW Components
public network
Node1a
shared storage
redo log instance 1 …
redo log instance 2 …
control files
database files
Node2a
Unbreakable Linux Unbreakable Linux
ORACM ORACM
clusterinterconnect
cache to cache
N3 N4 Nn
Oracle 9i RACinstance 1
Oracle 9i RACinstance 2
DB cache DB cache
concurrent access from
every node = “scale out”
more nodes = higher
availability
Linux Cluster Hardware
Cluster interconnects – FastEthernet, Gigabit Ethernet
Public networks – Ethernet, FastEthernet, Gigabit Ethernet
Memory, swap & CPU Recommendations– Each server should have a minimum of 512Mb of memory,
at least 1Gb swap space, and two CPUs.
Fiber Channel, SCSI, or NAS storage connectivity
Unbreakable Linux Distributions
Red Hat Enterprise Linux AS and ES United Linux 1.0
– SuSE Linux Enterprise Server 8 (SuSE Linux AG)– Conectiva Linux Enterprise Edition (Conectiva S.A.)– SCO Linux Server 4.0 (The SCO Group)– Turbolinux Enterprise Server 8 (Turbolinux)
Oracle will support Oracle products running with other distributions but will not support the operating system.
RAC Certification for Unbreakable Linux
Certification – Enterprise class OS distribution (e.g. RH AS, United Linux
1.0)– Clusterware (Oracle Cluster Manager only)– Network Attached Storage (e.g. Network Appliance filers)– Most SCSI and SAN storage are compatible – 32 bit and 64 bit Itanium 2 Intel based servers are certified.
For more details on software certification: http://technet.oracle.com/support/metalink/content.html
Discuss hardware configuration with your HW vendor
Linux IA64 requirements
Operating System Requirements – Red Hat Linux Advanced Server 2.1 operating system with
kernel 2.4.18-e.14.ia64.rpm – glibc 2.2.4-29 – Gnu gcc 2.96.0 release – Linux Header Patch 2.4.18 (available from Intel) – asynch libraries libaio-0.3.92-1 – (Oracle9i Release Notes
Release 2 (9.2.0.2.0) for Linux Intel on Itanium (64-bit) Part No. B10567-02 )
Set Expectations Appropriately
If your application will scale transparently on SMP, then it is realistic to expect it to scale well on RAC, without having to make any changes to the application code.
RAC eliminates the database instance, and the node itself, as a single point of failure, and ensures database integrity in the case of such failures
Planning: Define Objectives
Objectives need to be quantified/measurable– HA objectives
Planned vs unplanned Technology failures vs site failures vs human errors
– Scalability Objectives Speedup vs scaleup Response time, throughput, other measurements
– Server/Consolidation Objectives Often tied to TCO Often subjective
Build your Project Plan Partner with your vendors
– Multiple stakeholders, shared success Build detailed test plans
– Confirm application scalability on SMP before going to RAC optimize first for single instance
Address knowledge gaps and training– Clusters, RAC, HA, Scalability, systems management– Leverage external resources as required
Establish strict System and Application Change control– Apply changes to one system element at a time– Apply changes to first to test environment– Monitor impact of application changes on underlying system components
Define Support mechanisms and escalation procedures
Agenda Planning Best Practices
– Architecture– Expectation setting– Objectives and success criteria– Project plan
Implementation Best Practices– Infrastructure considerations– Installation/configuration– Database creation– Application considerations
Operational Best Practices– Backup & Recovery– Performance Monitoring and Tuning– Production Migration
Infrastructure Considerations
Architecture/Design– Eliminate SPOFs (Single Points of Failure)– Workload Distribution (load balancing) strategy– Systems management framework for monitoring and managing to
SLAs Hardware/Software
– Processing nodes – sufficient CPU to accommodate failure– Scalable I/O Subsystem
Use S.A.M.E.– Private Interconnect
Gige, UDP, switched– Patch levels and certification
Impementation Flowchart
Configure HW
Configure private interconnect
Install Unbreakable Linux
Install cluster manager 9.2.0.1
Install Oracle 9.2.0.1
Install 9.2.0.3 cluster manager
Install Oracle 9.2.0.3
Create database
Configure storage and install OCFS
Boot
Choose Language
Select Keyboard & Mouse
Choose – Advanced Server Option
Use DRUID for Partition Setup
Select Boot Loader
Configure Network
Configure Timezone
Account Configuration
Select Graphic Mode
Boot Floppy Creation
Installation Complete / Reboot
Installation Flowchart for Red Hat Linux AS 2.1
Install tips for Red Hat Linux AS 2.1
As documented in:– “Tips and Techniques: Install and Configure Oracle9i on Red Hat
Linux Advanced Server” by Deepak Patel, Oracle http://otn.oracle.com/tech/linux/pdf/installtips_final.pdf
Boot options – Always use Advanced Server install. As needed install required
packages. CD 1 to 3 has all rpm packages. CD 3 and 4 has source packages. CD 5 includes docs.
Memory– Based on physical memory on machine smp or enterprise kernel
is installed. ( <= 4 GB smp kernel and > 4 GB enterprise kernel ) Post Installation
– Add users, configure network and other administrative tasks after installation.
Install tips for United Linux 1.0
You must install the latest UnitedLinux kernel update! Oracle was certified against an update kernel, the original UL-1.0 kernel is NOT certified!
After installing United Linux 1.0, install Service Pack 2a from:
ftp://suse.us.oracle.com/pub/suse/i386/unitedlinux-1.0-iso/
You will also need to have the basic developments tools installed, like make, gcc_old(2.95.3), and the binutils package.
Full installation instructions: ftp://ftp.suse.com/pub/suse/i386/supplementary/commercial/Oracle/docs/920_sles8_install.pdf
Install tips for United Linux 1.0
Install the orarun.rpm package from either the SP2 CD
– <mountpoint>/UnitedLinux/i586/orarun-1.8-18.i586.rpm
or from – ftp://ftp.suse.com/pub/suse/i386/supplementary/
commercial/Oracle/sles-8/orarun.rpm
orarun.rpm update kernel (ie. shmmax, shmmin) UDP settings (256K) Installs and configures hangcheck-timer
Prepare Linux Environment
Follow these steps on EACH node of the cluster
– Set Kernel parameters in /etc/sysctl.conf
– Add hostnames to /etc/hosts file
– Establish file system or location for ORACLE_HOME (writable for oracle userid)
– Setup host equivalence for oracle userid (.rhosts)
Install the rpm’s on all nodes
Run ocfstool as root(configures /etc/ocfs.conf)
on all nodes
Run load_ocfs(insmod will load ocfs.o)
on all nodes
Create partition on the primary node
Run ocfstool to format andmount your new filesystem
Mount the new filesystemon all nodes
Edit rc.local or equivalent addload_ocfs and ‘mount –t
ocfs <device> <mountpoint’
Download the latest OCFS rpm’s from
www.ocfs.org
Installation Flowchart for OCFS
OCFS and Unbreakable Linux
Redhat– currently ships 4 flavors of the AS 2.1 kernel, viz., UP, SMP,
Enterprise and Summit (IBM x440)– Oracle provides a separate OCFS module for each of the kernel
flavors – Minor revisions of the kernel do not need a fresh build of ocfs– e.g., ocfs built for e.12 will work for e.16, e.18, etc.
United Linux– United Linux ships 3 flavors of its kernel, for the 2.4.19-64GB-SMP,
the 2.4.19-4GB and the 2.4.19-4GB-SMP kernel– OCFS 1.0.9 is supported on UL 1.0 Service Pack 2a or higher– OCFS build is not currently upward compatible with kernel (pre
SP3) must ensure OCFS build exists for each new Kernel version prior to upgrading kernel
OCFS and RAC
Maintains cache coherency across nodes for the filesystem metadata only
– Does not synchronize the data cache buffers across nodes, lets RAC handle that
OCFS journals filesystem metadata changes only– Filedata changes are journalled by RAC (log files)
Overcomes some limitations of raw devices on Linux– No limit on number of files– Allows for very large files (max 2TB)– Max volume size 32G (4K block) to 8T (1M block)
Oracle DB performance is comparable to raw kernel e.25 is strongly recommended for use with OCFS 1.0.9
(remove old kernel tuning parameters)
Install Tips for OCFS
Ensure OCFS rpm corresponds to kernel version– uname –r (i.e. 2.4.19-4GB)
Remember to also download rpm’s for OCFS “Support Tools” and “Additional Tools”
Download the dd/tar/cp rpm that supports o_direct Use rpm –Uv to install all 4 rpm’s on all nodes Use OCFS for Oracle DB files only, not Oracle
binaries (OCFS 1.0.x was not designed as a general purpose filesystem).
Installation Flowchart for oracm and Oracle
Install the oracm from the 9.2.0.1 CD-ROM
Configure ocmargs.oraand cmcfg.ora
Load the softdog and start with ./ocmstart.sh the cluster
manager on both nodes
Install 9.2.0.1 softwarewith the RAC option
Kill the oracm and watchdog process
modify ocmargs.oraand cmcfg.ora
(remove watchdog)
Load the hangcheck-timermodule with lsmod
Install the oracm from the 9.2.0.3 patchset
Start with ./ocmstart.sh the cluster manager
Install the 9.2.0.3patchset
Configure private interconnect and quorum device
Fix empty directory bug
Oracle Instance
Cluster Manager (including Node Monitor)
Hangcheck-timer
User-mode
Kernel-mode
Oracm maintains both, node status view and instance status view.
The hangcheck-timer monitors the kernel for hangs, and resets the node if needed.
Hangcheck NM, and CM Flow(After V9.2.0.2)
Post Installation
To enable asynchronous I/O must re-link Oracle to use skgaioi.o
Adjust UDP send / receive buffer size to 256K Larger Buffer Cache
– Create an in-memory file system on the /dev/shm (mount -t shm shmfs -o size=8g /dev/shm)
– To enable the extended buffer cache feature, set the init.ora paramter USE_INDIRECT_DATA_BUFFERS = true
Increasing Address Space – Default 1.7 GB of address space for its SGA.– See Metalink Note: 200266.1 for details and a sample
program.
Create RAC database using DBCA
Create Database Use DBCA to simplify DB creation
– Start gsd ( global services daemon ) on all nodes, if it is not already running.
Set MAXINSTANCES, MAXLOGFILES, MAXLOGMEMBERS, MAXLOGHISTORY, MAXDATAFILES (auto with DBCA)
Create tablespaces as locally Managed (auto with DBCA) Create all tablespaces with ASSM (auto with DBCA) Configure automatic UNDO management (auto with DBCA) Use SPFILE instead of multiple init.ora’s (auto with DBCA)
Validate RAC Configuration Instances running on all nodes
SQL> select * from gv$instance RAC communicating over the private Interconnect
SQL> oradebug setmypid SQL> oradebug ipcSQL> oradebug tracefile_name
/home/oracle/admin/RAC92_1/udump/rac92_1_ora_1343841.trc – Check trace file in the user_dump_dest:
SSKGXPT 0x2ab25bc flags info for network 0 socket no 10 IP 204.152.65.33 UDP 49197 sflags SSKGXPT_UP info for network 1 socket no 0 IP 0.0.0.0 UDP 0 sflags SSKGXPT_DOWN
RAC is using desired IPC protocol: Check Alert.log... cluster interconnect IPC version:Oracle UDP/IP IPC Vendor 1 proto 2 Version 1.0 PMON started with pid=2 ...
Use cluster_interconnects only if necessary
Configure srvconfig / srvctl SRVCTL uses information from srvconfig
– Reads $ORACLE_HOME/srvm/config /srvConfig.loc information File can be a RAW Device or OCFS file
Srvconfig -init gsd must be running Add ORACLE_HOME
– $ srvctl add database -d db_name -o oracle_home [-m domain_name] [-s spfile]
Add instances (for each instance enter the command)– $ srvctl add instance -d db_name -i sid -n node
Application Deployment
Same guidelines as single instance– SQL Tuning– Sequence Caching– Partition large objects– Use different block sizes– Tune instance recovery– Avoid DDL– Use LMT’s and ASSM as noted earlier
Agenda Planning Best Practices
– Architecture– Expectation setting– Objectives and success criteria– Project plan
Implementation Best Practices– Infrastructure considerations– Installation/configuration– Database creation– Application considerations
Operational Best Practices– Backup & Recovery– Performance Monitoring and Tuning– Production Migration
Operations
Same DBA procedures as single instance, with some minor, mostly mechanical differences.
Managing the Oracle environment– Starting/stopping cluster services (ocmstart.sh)– Starting/stopping gsd– Managing multiple redo log threads
Startup and shutdown of the database– Use srvctl
Backup and recovery Performance Monitoring and Tuning Production migration
Operations: srvconfig / srvctl Use SRVCTL to administer your RAC database
environment. – OEM and the Oracle Intelligent Agent use the configuration
information that SRVCTL generates to discover and monitor nodes in your cluster.
Global Services Daemon (GSD) receives requests from SRVCTL to execute administrative job tasks, such as startup or shutdown.
– GSD must be started on all the nodes in your RAC environment so that the manageability features and tools operate properly. (GSDCTL)
Operations: Backup & Recovery
RMAN is the most efficient option for Backup & Recovery– Managing the snapshot control file location.– Managing the control file autobackup feature.– Managing archived logs in RAC – choose proper archiving scheme. – Node Affinity Awareness
RMAN and Oracle Net in RAC apply– you cannot specify a net service name that uses Oracle Net
features to distribute RMAN connections to more than one instance.
Oracle Enterprise Manager– GUI interface to Recovery Manager
Performance Monitoring and Tuning Tune first for single instance 9i Use Statspack:
– Separate 1 GB tablespace for Statspack– snapshots at 10-20 min intervals during stress testing, hourly during normal
operations– Run on all instances, staggered
Supplement with scripts/tracing – Monitor V$SESSION_WAIT to see which blocks are involved in wait events– Trace events like 10046/8 can provide additional wait event details– Monitor Alert logs and trace files, as on single instance
Oracle Performance Manager RAC-specific views Supplement with System-level monitoring
– CPU utilization never 100%– I/O service times never > acceptable thresholds– CPU run queues at optimal levels
Performance Monitoring and Tuning Obvious application deficiency on a single node can’t be solved by
multiple nodes.– Single points of contention. – Not scalable on SMP– I/O bound on single instance DB
Tuning on single instance DB to ensure applications scalable first– Identify/tune contention using v$segment_statistics to identify objects
involved– Concentrate on the top 5 Statspack timed events if majority of time is
spent waiting– Concentrate on bad SQL if CPU bound
Maintain a balanced load on underlying systems (DB, OS, storage subsystem, etc. )
– Excessive load on individual components can invoke aberrant behaviour.
Performance Monitoring and Tuning
Deciding if RAC is the performance bottleneck– Amount of Cross Instance Traffic
Type of requests Type of blocks
– Latency Block receive time buffer size factor bandwidth factor
Production Migration
Adhere to strong Systems Life Cycle Disciplines– Comprehensive test plans (functional and stress)– Rehearsed production migration plan– Change Control
Separate environments for Dev, Test, QA/UAT, Production
System AND application change control Log changes to spfile
– Backup and recovery procedures– Security controls– Support Procedures
Next Steps….
Recommended sessions– List 1 or 2 sessions that complement this session
Recommended demos and/or hands-on labs– List of or two demos or labs that will let them see this
product in action. See Your Business in Our Software
– Visit the DEMOgrounds for a customized architectural review, see a customized demo with Solutions Factory, or receive a personalized proposal. Visit the DEMOgrounds for more information.
Relevant web sites to visit for more information– List urls here.
Reminder – please complete the OracleWorld online session survey
Thank you.
Resources RedHat Linux
– http://www.redhat.com/oracle/
Linux Center - Technical White Papers & Documentation– http://otn.oracle.com/tech/linux/tech_wp.html
“Tips and Techniques: Install and Configure Oracle9i on Red Hat Linux Advanced Server” by Deepak Patel, Oracle Corporation
• http://otn.oracle.com/tech/linux/pdf/installtips_final.pdf
“Tips and Techniques: Install and Configure Oracle9i on SLES8 / United Linux 1.0
• http://www.suse.com/en/business/certifications/certified_software/oracle/db/9iR2_sles8.html
United Linux 1.0 Resources
United Linux– http://www.unitedlinux.com
SuSE– http://www.suse.com/us/business/products/server/sles/index.html
Connectiva– http://www.connectiva.com
SCO Group (Formerly Caldera System) - http://www.ebizenterprises.com/page1.asp?p=463
TurboLinux– http://www.turbolinux.com/
Recommended one-off patches
Bug 2820871 - ORA-29740 NODE EVICTION DESIGN ALGORITHM AND ABRUPT TIME CHANGEARU: 9.2.0.3 ARU 4161735 completed for LINUX Intel
Bug 2420930 - GET ORA-600 [KSXPMPRP1] DURING STARTUP IN RAC MODE WITH LARGER BUFFERS. This was mysteriously included in 9.2.0.2, but not in 9.2.0.3. Bug 2875050 was opened for this issue. ARU: 9.2.0.3 ARU 4202164completed for LINUX Intel
Bug 2420930 - GET ORA-600 [KSXPMPRP1] DURING STARTUP IN RAC MODE WITH LARGER BUFFERS Bug 2922471 – Fractured block found during crash/instance recovery. Not an Oracle bug. Do not use ‘intr’ for the mount option.
Recommended one-off patches
Bug:2844009 - MISSING LIBCXA.SO.3 LIBRARY ISSUE IN PSR 9203. ARU: 9.2.0.3 ARU 4046387 completed for LINUX Intel
Bug 2779294 – node_list does not populated into oraInventory/ContentsXML/inventory.xml. opatch install will only apply to local node. Workaround is editing inventory.xml documented in bug 2742686.
Bug 2646914, 2675090, 2706220 and 2695783 - ORA-600
[KCCSBCK_FIRST], [2] on linux and W2K platform after installing 9.2.0.2. Very important patch, missing from 9.2.0.3ARU: 9.2.0.3 ARU 4110670 completed for LINUX Intel ·
Hangcheck-timer and Oracle Cluster Manager
Download Patch 2594820 from Metalink– #rpm -ivh <hangcheck-timer RPM name>
Detaching watchdogd from the Cluster Manager (Bug 2495915)
The removal of the watchdogd ORACLE_HOME/oracm/admin/cmcfg.ora
– WatchdogTimerMargin – WatchdogSafetyMargin
KernelModuleName=hangcheck-timer CMDiskFile from optional to mandatory
– CM quorum partition of cluster participation.
Hangcheck-timer and Oracle Cluster Manager
remove or comment out from the /etc/rc.local file:
/sbin/insmod softdog nowayout=0 soft_noboot=1 soft_margin=60
ADD to rc.local, execute as root to load
/sbin/insmod hangcheck-timer.o hangcheck_tick=30 hangcheck_margin=180
Hangcheck-timer and Oracle Cluster Manager
inclusion of the hangcheck-timer kernel module Parameter Service Value----------------- -----------------
---------------hangcheck_tick hangcheck-timer 30 seconds
hangcheck_margin hangcheck-timer 180 seconds
KernelModuleName oracm hangcheck-timer
MissCount oracm > hangcheck_tick
hangcheck_margin
(> 210 seconds)
Hangcheck-timer and Oracle Cluster Manager
cmcfg.ora example- HeartBeat=15000- ClusterName=Oracle Cluster Manager, version 9i- KernelModuleName=hangcheck-timer- PollInterval=1000- MissCount=215- PrivateNodeNames=int-node1 int-node2- PublicNodeNames=node1 node2- ServicePort=9998- CmDiskFile=/ocfsdisk1/quorum/quorumfile- HostName=int-node1
Hangcheck-timer and Oracle Cluster Manager
Parameters for ocmargs.ora- oracm- norestart 1800
Linux Monitoring and Configuration Tools
- Overall tools sar, vmstat- CPU /proc/cpuinfo, mpstat, top- Memory /proc/meminfo, /proc/slabinfo, free- Disk I/O iostat- Network /proc/net/dev, netstat, mii-tool - Kernel Version and Rel. cat /proc/version - Types of I/O Cards lspci –vv- Kernel Modules Loaded lsmod, cat /proc/modules - List all PCI devices (HW) lspci –v- Startup changes /etc/sysctl.conf, /etc/rc.local - Kernel messages /var/log/messages, /var/log/dmesg - OS error codes /usr/src/linux/include/asm/errno.h- OS calls /usr/sbin/strace-p
Post Installation
Increasing Address Space Default 1.7 GB of address space for its SGA. Shutdown all instances of Oracle cd $ORACLE_HOME/lib cp -a libserver9.a libserver9.a.org
– to make a backup copy cd $ORACLE_HOME/rdbms/lib genksms -s 0x15000000 >ksms.s
– lower SGA base to 0x15000000 make -f ins_rdbms.mk ksms.o
– compile in new SGA base address make -f ins_rdbms.mk ioracle (relink)
Post Installation
Increasing Address Space Cont.
sysctl –w kernel.shmmax=3000000000
Lower process base – Find out the pid of the process (shell) from where oracle will
be started using ps (Oracle - echo $$)
– changing /proc/$pid/mapped_base to 0x10000000 and restarting oracle
Metalink Note: 200266.1
Variable SGA
Reserved for kernel
DB Buffers(SGA)
Default
Code, etc.
0xFFFFFFFF
0xC0000000
0x500000000x40000000
0x00000000
Variable SGA
Reserved for kernel
DB Buffers(SGA)
After Relink
Code, etc.
0xFFFFFFFF
0xC0000000
0x150000000x100000000x00000000
mapped_base(/proc/<pid>/mapped_base)
sga_base(relink Oracle)
Lowering of mapped base
Post Installation
Post Installation
Larger Buffer Cache does buffer cache increase with larger SGA
Create an in-memory file system on the /dev/shm mount -t shm shmfs -o size=8g /dev/shm
To enable the extended buffer cache feature, set the init.ora paramter
USE_INDIRECT_DATA_BUFFERS = true
Don’t Use dynamic cache parameters DB_CACHE_SIZE DB_#K_CACHE_SIZE
Limitations apply to the extended buffer cache feature on Linux:You cannot change the size of the buffer cache while the instance is running.
You cannot create or use tablespaces with non-standard block sizes.
Post Installation
Adjust send / receive buffer size to 256K Tuning the default and maximum window sizes:- /proc/sys/net/core/rmem_default - default receive window- /proc/sys/net/core/rmem_max - maximum receive
window- /proc/sys/net/core/wmem_default - default send window - /proc/sys/net/core/wmem_max - maximum send window - sysctl -w net.core.rmem_max=262144 - sysctl -w net.core.wmem_max=262144 - sysctl -w net.core.rmem_default=262144- sysctl -w net.core.wmem_default=262144
Post Installation
To enable asynchronous I/O must re-link Oracle to use skgaioi.o
– cd to $ORACLE_HOME/rdbms/lib– make -f ins_rdbms.mk async_on – make -f ins_rdbms.mk ioracle
– set 'disk_asynch_io=true' (default value is true) – set 'filesystemio_options=asynch‘ (RAW Only)