Thursday Jan 06, 2011
Wednesday Aug 25, 2010
Monday Jun 28, 2010
By Chang Shu on Jun 28, 2010
By Chang Shu on Jun 28, 2010
Thursday Jun 03, 2010
By Chang Shu on Jun 03, 2010
I am asked by customers from time to time regarding if some new Solaris 10 features are supported by DB2, here I find the following support statements from the Installation Requirements section in the DB2 Information Center:
I have published an article regarding how to deploy DB2 in Solaris Containers/Zones. I'll post new blog entries to talk about how to deploy DB2 in LDoms and the tips to use ZFS very soon.
DB2 database products support the following Solaris concepts:
- Solaris Logical Domains (LDoms)
- Solaris Zones
- ZFS filesystems
Monday Oct 12, 2009
Using Sun Storage F5100 Flash Array together with Sun Storage J4400 to Improve Query Performance for Data Warehousing Workload
By Chang Shu on Oct 12, 2009
Data warehousing applications are generally I/O bound in nature. And because there are more reads than writes, this kind of workload should be able to take more advantage of the F5100 Flash Array as flash devices generally favor reads over writes.
This write-up presents the results of a database study that I did recently to compare the performance of storage architectures taking advantage of Sun Storage F5100 Flash Array with storage architecture based only on traditional hard disks.
The testing environment was built using a Sun Fire X4275 server with two quad-core Intel Xeon X5570 processors and 72 GB of RAM to host the DB2 database server. The Sun Fire X4275 server runs the Solaris 10 OS (Update 8) and the DB2 UDB V9.5 Fixpak 4. Four SAS HBA cards installed in the database server to support the access to four array domains of the F5100 Flash Array, and up to 960 GB of raw storage (40 Sun Flash Modules). Host mirroring across HBAs and domains can be used to increase data availability, which reduces the usable capacity to 480 GB. The second SAS channel of two HBAs are connected to a Sun Storage J4400, which contains 24 x 146 GB disk drives. Two Storage I/O Modules (SIM 0 and SIM 1) are used with the J4400 to support dual-path. A Sun Fire X4200 is used as the workload driver with two duo-core AMD Opteron processors and 16 GB RAM.
The deployment for the testing is shown as the following diagram.
Due to time limitation, the testing was performed against a small data warehouse. The size of the table spaces is around 200GB. Access to index table spaces and user temporary table space on the Sun Storage F5100 Flash Array is through four SAS HBAs. Access to the production data table spaces and log containers are through 24-disk based RAID 0 volume in J4400. The page size is 32KB. A UFS file system is created for each volume and mounted with the “forcedirectio” option.
Both atomic queries such as sorts / joins, and advanced queries containing complex business logic were both tested in order to compare the performance gains of using F5100 Flash Array in both cases. I/O Per Second (IOPS) and I/O bandwidth are the main performance metrics for the measurement.
Sorts / Joins
DB2 use temporary table space to store data during its execution in a transient or temporary work table. For e.g., when doing sorts and joins, if the the size of the sort heap can not fit in all temporary data, DB2 overflows the data to the temporary table space.
Three joins including nested loop join, merge join and hash join were perform during the test process. The I/O activity for disk-only test is as the follows:
The average disks usage is measured for each individual disk in the J4400, the usage for the whole volume is actually between 48-100%.
In Comparison, the I/O activity for flash / disk system is as below:
putting the temporary table space in the F5100 Flash Array, the
IOPS is increased from 5629 to 12983, which is 3.2 times improvement.
These queries contain more advanced business logic, mixed with both sequential reads and random reads. Besides data table spaces, temporary table spaces and index table spaces are also heavily accessed during the queries execution.
The I/O activity for disk-only test is as the follows:
The I/O activity for the flash / disk system is as below:
The IOPS improves 77% to 11345 compared to 6416 in the disk-only system. The queries execution time improves 10.8 times to 180 seconds compared to 1952 seconds in the disk-only system.
Adding a Sun Storage F5100 Flash Array to off-load index and temporary table spaces I/O processing from a disk system to flash-based storage can improve system I/O performance because index and temporary table spaces I/O have been moved to the flash device so there is less workload for the disk to support, and the spinning disk can get the remaining work done more quickly.
The above testing shows how the combination
of flash and disk technology can be applied to improve IBM DB2 UDB
database performance for data warehousing workload. In the experiments,
indexes and temporary tablespaces are stored on the F5100 Flash Array,
which improves the overall performance by reducing the application response
time and increasing the I/O throughput. Hybrid flash/disk technology is becoming a practical solution for database applications.
Tuesday Sep 22, 2009
By Chang Shu on Sep 22, 2009
Recently when I was installing DB2 V9.5 on a brand new Sun system running Solaris x64, I got a coredump when creating a DB2 instance by 'db2icrt' command. The error message is :
"Segmentation Fault - core dumped"
This looks like a memory access error. But it's also very confusing because I had the same version of DB2 running on another server and I never had the problem of creating an instance on it.
Spending some time poking around on both systems, I finally understood what's going wrong on my new system - I had a typo in the server name in /etc/hosts file! As the 'hostname' returned a wrong name, DB2 got unknown host error when ping it, which triggered the segmentation fault. Problem solved, though the error message is a bit misleading.
Monday Apr 13, 2009
Thursday Mar 26, 2009
By Chang Shu on Mar 26, 2009
My new article - "Deploying DB2 Database on the Sun Storage 7000 Unified Storage System" has been published as a Sun Blueprint.
You can also go to the wiki page to comment and rate it.
Here is the brief introduction.
For DB2 applications, Sun Storage 7000 Unified Storage Systems meet a range of functional requirements for availability, capacity, and performance. This Sun BluePrints™ article describes the steps needed to configure and install a DB2 database in a Sun Storage 7000 Unified Storage System environment. The article addresses the following topics:
• Preparing a Sun Storage 7000 Unified Storage System for DB2 database storage
• Preparing a server running the Solaris™ Operating System (Solaris OS) to use NFS file systems or Internet SCSI (iSCSI) logical unit numbers (LUNs)
• Installing the DB2 software on the server and creating a database on the storage system
• Separating database transaction log files from data files and storing them on the storage system
• Taking a snapshot of an online DB2 database and recovering from the snapshot
Wednesday Mar 11, 2009
Monday Nov 10, 2008
By Chang Shu on Nov 10, 2008
Today, Sun announces the Sun Storage 7000 Unified Storage Systems a.k.a. Amber Road, the first Open Storage appliances. I tried out the product a while ago, with running DB2 workload to use it as database table space containers and log containers. What impressed me most is its simplicity in administration and comprehensive analytics. There are no commands needed for installation and configuration, all these can be done via click and drag in GUI interface. Dtrace is used underneath to trouble shoot, analyze, and optimize the system, and all these features are presented via graphics.
Running a DB2 database with data and transaction log files stored on Sun Storage 7000 Unified Storage Systems has several advantages:
Extremely Fast Backup: Backup performance can be significantly improved using Snapshot copies in conjunction with DB2's set write suspend and set write resume commands. Snapshot copies can be created in a matter of seconds, regardless of the size of the database. This reduces the database backup window from hours to seconds and allows DBAs to take frequent full database backups without having to take the database offline.
Quick Recovery: Since there is no data copying involved, an incredible amount of time is saved as the file system is put back to the original state it was at the time the Snapshot was taken.
Availability and Reliability: The Amber Road Snapshot can create database backup in a matter of seconds without bringing a database down. Amber Road provides RAID-Z which is more reliable than RAID-5. It allows for better distribution of parity and eliminates the "RAID-5 write hole" (in which data and parity become inconsistent after a power loss). Data and parity is striped across all disks within a RAID-Z group.
No Impact on System Response Time: Because a Snapshot copy is simply a picture of the file system at a specific pint-in-time and creating a database backup using Snapshot does not involve actual data I/O, the process of backing up a database virtually has no performance impact on the system response time.
In the future blogs, I will introduce some hands-on examples on how to use the Sun Storage 7000 Unified Storage Systems with DB2.
Thursday Nov 06, 2008
By Chang Shu on Nov 06, 2008
DB2 Express-C is a free version of IBM DB2 database server. But it is not a crippled or trial version of DB2. It shares the same code as the other commercial DB2 editions and it has a very generous license, which doesn't impose limits on your database. This means there are no connection limits, no database size limits, and no user limits. It supports 2 cores and 2 GB RAM for absolutely free. Compared with SQL Server 2005 Express and Oracle 10g Express Edition that have limitation on DB size, DB2 Express-C has the most generous offering.
In Allan Packer's blog “Are Proprietary Databases Doomed?”, he pointed out that for some companies database licenses have become their single biggest IT cost. The impact is probably greater on small and medium-sized companies that don't have the same ability to command the hefty discounts that larger companies typically enjoy from database vendors. Fortunately we have more choices today. If you don't want to cost an arm or leg on databases, you can either come to the camp of Open Source Databases, or for any reasons you don't want the Open Source Databases, DB2 Express-C could be a good option for you.
The latest version of DB2 Express-C v9.5 for Solaris 10 x64 had been released for months. You can get it from here. Besides Solaris 10 for x64, you can also deploy Express-C on OpenSolaris. OpenSolaris contains the subset of the source code for the Solaris Operating System, but with an open source license. It is a viable alternative to Linux but with more unique features. Among the familiar Sun features are the powerful DTrace dynamic tracing tool and the impressive ZFS filesystem, neither of which are likely to make it to Linux due to licensing and personality conflicts.
If you are familiar with Solaris 10, then there is no gap for you to use OpenSolaris. Actually it is more easier to install and deploy OpenSolaris, either on your x64/x86 server, or on your laptop, or on your SPARC server (yep, the coming OpenSolaris 2008.11 release will support SPARC).
To deploy DB2 Express-C V9.5 on OpenSolaris, you don't need to bother to read any installation/configuration documents for these two products, if you know how to deploy DB2 UDB on Solaris 10. The DB2 utilities for Solaris platform such as db2osconf and db2ptree work the same way as DB2 UDB on Solaris 10. Any everything else just works fine as well. Because there is almost no change in the way of installation and configuration, the only exception is that DB2 Express-C doesn't support non-root installation.
Since OpenSolaris supports Solaris Containers technology, you can consolidate DB2 Express-C with other applications in different containers on a single server. Dedicated CPUs and memory caps can be assigned to each container for resource isolation. For e.g.,
global# zonecfg -z myzone zonecfg:myzone> add dedicated-cpu zonecfg:myzone:dedicated-cpu> set ncpus=1-2 zonecfg:myzone:dedicated-cpu> end zonecfg:myzone> add capped-memory zonecfg:myzone:capped-memory> set physical=2g zonecfg:myzone:capped-memory> set swap=20g zonecfg:myzone:capped-memory> end zonecfg:myzone> exit
DB2 Express-C plus OpenSolaris provides a reliable, secure and scalable data server solution, and it is costs-free!
Who says that – The best things in life are free!
Friday Oct 10, 2008
By Chang Shu on Oct 10, 2008
First of all, before doing anything on the system, ensure that the system's firmware is up-to-date. This is especially important for running DB2 on CMT systems, which have a hypervisor that sits between the hardware and operating system. The recommended System Firmware version for T5440 is 7.2.0 or above. Note that DB2 can crash on T51x0 and T52x0 systems using early firmware versions. See IBM's tech notes for more information. The latest versions of Sun System Firmware can be downloaded from http://www.sun.com/bigadmin/patches/firmware.
T5440 comes up with Solaris 10 5/08 release. The LDoms on T5440 supports Solaris 10 11/06 and above. The required kernel patch is 137111-06 or above, and the nxge patch 138048-05 for software Large Segment Offload (LSO) support. It is always recommended to upgrade to the latest update release of Solaris 10.
Using large memory pages with DB2 on Solaris is always a good practice. Large memory pages are intended to improve the performance of the kernel and database applications by improving utilization of the processor's TLB. DB2 mainly uses large pages for database shared memory, which includes bufferpools, database heap, package cache, lock heap, catalog cache and utility heap. The DB2 database shared memory is allocated by Intimate Shared Memory (ISM) segments. Recent Solaris 10 updates have improved default behavior on the allocation of large pages. By default, Solaris 10 5/08 will use a maximum of 4M pages for DB2 shared memory segments. To enable 256M pages, add the following tunable to /etc/system and reboot.
\*enable 256M pages
For TCP/IP tunables, run the following commands from the command line as the root user:
ndd -set /dev/tcp tcp_xmit_hiwat 262144
ndd -set /dev/tcp tcp_recv_hiwat 262144
DB2 OLTP applications may benefit from Fixed Priority scheduling class on T5440. DB2 processes in the fixed priority class stay at a fixed priority level and with a fixed time quantum. So there are no frequent ping-pong of priorities and related changes in their time quantum as those in Time Sharing scheduling class (the default class for all processes). To use the Fixed Priority (FX) scheduling class, just just run the priocntl(1) command from the command line as the root user:
# priocntl -s -c FX -i projid <projid for a db2 instance>
"ps -ecf <DB2-PID>" can print out the scheduling class and its priority assigned for a db2 process. The default priority "0" usually works well for DB2.
As T5440 is a NUMA architecture, memory latency should be considered when running database applications that are very sensitive to memery latency. Fortunately, the threaded design of UltraSPARC T2 Plus chip acts to minimize the impact of memory latency. DB2 also supports the optimal placement of a database partition's processes and memory, which means a database partition's processes and memory can be restricted to an Locality Group (lgroup), so there are lower memory latencies and increased performance. The following shows how to achieve this.
In my experiment, I created 3 Solaris Containers on a T5440, and deployed one DB2 instance in each container, one DB2 instance in the global zone. So altogether there are 4 DB2 instances on the system. Four resource pools were created for each zone:
create pset db1_pset (uint pset.min = 64; uint pset.max=64)
create pset db2_pset (uint pset.min = 64; uint pset.max=64)
create pset db3_pset (uint pset.min = 64; uint pset.max=64)
create pool db1_pool (string pool.scheduler="FX")
create pool db2_pool (string pool.scheduler="FX")
create pool db3_pool (string pool.scheduler="FX")
associate pool db1_pool (pset db1_pset)
associate pool db2_pool (pset db2_pset)
associate pool db3_pool (pset db3_pset)
Here are the commands to create one of the non-global zone:
# zonecfg -z db2svr1
db2svr1: No such zone configured
Use 'create' to begin configuring a new zone.
zonecfg:db2svr1> set zonepath=/export/home/zones/db2svr1
zonecfg:db2svr1> set autoboot=true
zonecfg:db2svr1> add net
zonecfg:db2svr1:net> set address=184.108.40.206
zonecfg:db2svr1:net> set physical=nxge0
zonecfg:db2svr1> add fs
zonecfg:db2svr1:fs> set dir=/db2data
zonecfg:db2svr1:fs> set special=/dev/dsk/c4t600A0B8000388C940000039048BE7480d0s4
zonecfg:db2svr1:fs> set raw=/dev/rdsk/c4t600A0B8000388C940000039048BE7480d0s4
zonecfg:db2svr1:fs> set type=ufs
zonecfg:db2svr1> add fs
zonecfg:db2svr1:fs> set dir=/db2log
zonecfg:db2svr1:fs> set special=/dev/dsk/c4t600A0B8000388C940000038E48BE72A4d0s4
zonecfg:db2svr1:fs> set raw=/dev/rdsk/c4t600A0B8000388C940000038E48BE72A4d0s4
zonecfg:db2svr1:fs> set type=ufs
zonecfg:db2svr1> add fs
zonecfg:db2svr1:fs> set dir=/opt/IBM
zonecfg:db2svr1:fs> set special=/opt/IBM
zonecfg:db2svr1:fs> set type=lofs
zonecfg:db2svr1:fs> set options=[rw,nodevices]
zonecfg:db2svr1> set pool=db1_pool
Each non-global has its local file systems mounted, and it can access the DB2 executables in the global zone.
# zoneadm list -vi
ID NAME STATUS PATH BRAND IP
0 global running / native shared
1 db2svr1 running /export/home/zones/db2svr1 native shared
2 db2svr2 running /export/home/zones/db2svr2 native shared
3 db2svr3 running /export/home/zones/db2svr3 native shared
By binding the zone to a resource pool, for DB2 processes running inside the zone, the percentage of memory accesses that are statisfied locally should increase dramatically. This approach generally got ~10% performance improvment for DB2.
Use poolstat(1) command monitor the resource pool cpu utilization:
# poolstat 5
id pool size used load
0 pool_default 64 60.3 253
1 db1_pool 64 55.5 240
2 db2_pool 64 51.7 249
3 db3_pool 64 53.2 252
This way of monitoring makes it straight forward to see which zones or applications are saturated the CPU. Then you can adjust the resources accordingly to fit their needs.
With Solaris Container technology, we can have the flexibility to maximize DB2 performance by running multiple DB2 instances on T5440. You can also take advantage of other zero cost virtualization technologies like LDoms to scale or consolidate solutions on a single system.
This is a blog to talk about technical information regarding running IBM DB2 database on Solaris.
- DB2 on SPARC T3 Tuning Tips
- Configuring JProfiler for Oracle WebLogic 11g Application Server on Solaris
- Tuning tips for ZFS with IBM DB2
- Scaling IBM DB2 Database Application on Sun Fire X4470
- Running IBM DB2 in Oracle VM Server for SPARC (LDoms)
- More Blog Entries
- DB2 Support Statements for Solaris 10 Containers, LDoms, and ZFS
- Using Sun Storage F5100 Flash Array together with Sun Storage J4400 to Improve Query Performance for Data Warehousing Workload
- Confusing coredump when running db2icrt on Solaris
- Get a Performance Jump on Sun Blade X6270