How To Check Io Error In Solaris
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Performance troubleshooting : Disk (I/O) performance issues An I/O performance bottleneck can be due to a disk or even due to a HBA or a HBA driver. The command iostat (Input output statistics) help us to get started with analyzing a disk I/O bottleneck issue.A standard iostat output would look like :# iostat -xn 1 5 extended device statistics r/s solaris disk io performance w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device 293.1 0.0 37510.5 0.0 0.0 asvc_t iostat solaris 31.7 0.0 108.3 1 100 c0t0d0 294.0 0.0 37632.9 0.0 0.0 31.9 0.0 108.6 0 100 c0t0d0 293.0 0.0 37504.4 0.0 0.0 31.9 0.0 solaris check disk status 1032.0 0 100 c0t0d0 294.0 0.0 37631.3 0.0 0.0 31.8 0.0 108.1 1 100 c0t0d0 294.0 0.0 37628.1 0.0 0.0 31.9 0.0 108.6 1 100 c0t0d0The various options that can be used with iostat are : -x --> Extended disk mount i/o error solaris statistics. This prints a line per device and provides the breakdown that includes r/s, w/s, kr/s, kw/s, wait, actv, svc_t, %w, and %b. -t --> Print terminal I/O statistics. -n --> Use logical disk names rather than instance names. -c --> Print the standard system time percentages: us, sy, wt, id. -z --> Don't print lines having all zeros.The meaning of each column value in the iostat output is :r/s reads per second w/s writes per second kr/s kilobytes read
Solaris 10 Performance Monitoring
per second kw/s kilobytes written per second wait average number of transactions waiting for service (queue length) actv average number of transactions actively being serviced (removed from the queue but not yet completed) svc_t average response time of transactions, in milliseconds %w percent of time there are transactions waiting for service (queue non-empty) %b percent of time the disk is busy (transactions in progress) wsvc_t average service time in wait queue, in milliseconds asvc_t average service time of active transactions, in milliseconds wt the I/O wait time is no longer calculated as a percentage of CPU time, and this statistic will always return zero.The first line in the iostat output is the summary since boot. This line will give you a rough idea of average server I/O on the server. This could be very useful to compare the server I/O performance at the time of performance bottleneck. Now if you see the asvc_t column you would see a constant high value. Generally a value more than 30 to 40 ms is considered to be high. But you can safely ignore a spike of 200 ms in the asvc_t column. Here the interval was 1 sec with a count of 5.Check for Disk FailuresDisk failure could also be a major, infact the only reason in many disk I/O bottleneck issues. To check the disk failure :# iostat -xne extended device statistics ---- errors --- r/s w/s kr/s k
Commands 2.Managing User Accounts and Groups (Overview) 3.Managing User Accounts and Groups (Tasks) 4.Booting and Shutting Down an Oracle Solaris System 5.Working With Oracle Configuration Manager 6.Managing Services (Overview) 7.Managing Services (Tasks) 8.Using the Fault Manager 9.Managing
Iostat Hard Errors Solaris
System Information (Tasks) 10.Managing System Processes (Tasks) 11.Monitoring System Performance (Tasks) Where to how to check i/o error in solaris Find System Performance Tasks System Performance and System Resources Processes and System Performance About Monitoring System Performance Monitoring Tools Displaying System man iostat solaris Performance Information (Task Map) Displaying Virtual Memory Statistics (vmstat) How to Display Virtual Memory Statistics (vmstat) How to Display System Event Information (vmstat -s) How to Display Swapping Statistics (vmstat -S) How to Display http://thegeekdiary.com/solaris-performance-troubleshooting-series-disk-io-performance-issues/ Interrupts Per Device (vmstat -i) Displaying Disk Utilization Information (iostat) How to Display Disk Utilization Information (iostat) How to Display Extended Disk Statistics (iostat -xtc) Displaying Disk Space Statistics (df) How to Display Disk Space Information (df -k) Monitoring System Activities (Task Map) Monitoring System Activities (sar) How to Check File Access (sar -a) How to Check Buffer Activity (sar -b) How to Check System Call Statistics (sar https://docs.oracle.com/cd/E23824_01/html/821-1451/spmonitor-4.html -c) How to Check Disk Activity (sar -d) How to Check Page-Out and Memory (sar -g) Checking Kernel Memory Allocation How to Check Kernel Memory Allocation (sar -k) How to Check Interprocess Communication (sar -m) How to Check Page-In Activity (sar -p) How to Check Queue Activity (sar -q) How to Check Unused Memory (sar -r) How to Check CPU Utilization (sar -u) How to Check System Table Status (sar -v) How to Check Swapping Activity (sar -w) How to Check Terminal Activity (sar -y) How to Check Overall System Performance (sar -A) Collecting System Activity Data Automatically (sar) Running the sadc Command When Booting Running the sadc Command Periodically With the sa1 Script Producing Reports With the sa2 Shell Script Setting Up Automatic Data Collection (sar) How to Set Up Automatic Data Collection 12.Managing Software Packages (Tasks) 13.Managing Disk Use (Tasks) 14.Scheduling System Tasks (Tasks) 15.Setting Up and Administering Printers by Using CUPS (Tasks) 16.Managing the System Console, Terminal Devices, and Power Services (Tasks) 17.Managing System Crash Information (Tasks) 18.Managing Core Files (Tasks) 19.Troubleshooting System and Software Problems (Tasks) 20.Troubleshooting Miscellaneous System and Software Problems (Tasks) Index Displaying Disk Utilization Information (iostat) Use the iostat command to report statistics about disk
may be broken down as follows for a typical I/O operation: POSIX: Application calls a POSIX library interface. (These frequently map directly to system calls, except for the asynchronous https://www.princeton.edu/~unix/Solaris/troubleshoot/diskio.html interfaces. These latter work via pread and pwrite.) System Call: The relevant node and vfs http://unixadminschool.com/blog/2012/02/solaris-troubleshooting-disk-io-performance-issues/ system calls are: vnode system calls: close() creat() fsync() ioctl() link() mkdir() open() read() rename() rmdir() seek() unlink() write() vfs system calls: mount() statfs() sync() umount() VOP: The vnode operations interface is the architectural layer between the system calls and the filesystems. DTrace provides the best way to examine this layer. Starting in version 0.96, the DTrace Toolkit's vopstat how to command allows direct monitoring at this level. Filesystems: There is some discussion of filesystem tuning and filesystem caching at the bottom of this page. Further information on troubleshooting a particular filesystem is contained in each filesystem's web page. (This site contains pages for NFS, UFS and ZFS filesystems.) Physical Disk I/O: This is the portion of the I/O that involves the transfer of data to or from the physical hardware. Traditionally, I/O troubleshooting focuses how to check on this portion of the I/O process. McDougall, Mauro and Gregg suggest that the best way to see if I/O is a problem at all is to look at the amount of time spent on library and system calls via DTrace. For example, the DTrace Toolkit's procsystime utility tracks time spent on each system call. Similarly, the dtruss -t syscall -p PID command can examine the time spent on a particular system call for a process. The truss -D -p PID command also reveals the time spent by a process in I/O system calls, but it imposes a severe performance penalty. If the system call statistics reveal a problem, we should look at the raw disk I/O performance. Physical Disk I/O The primary tool to use in troubleshooting disk I/O problems is iostat. sar -d provides useful historical context. vmstat can provide information about disk saturation. For Solaris 10 systems, dtrace can provide extremely fine-grained information about I/O performance and what is causing any utilization or saturation problems. The DTrace Toolkit provides a number of ready-to-use scripts to take advantage of DTrace's capabilities. To start, use iostat -xn 30 during busy times to look at the I/O characteristics of your devices. Ignore the first bunch of output (the first group of output is summary statis
LinkedIn How to Use this Site ? Solaris Troubleshooting : Disk i/o Performance Issues February 17, 2012By RamdevThis post is to highlight some of the steps needed to diagnose if an issue is in fact a disk performance issue or not. And if it is, what data will be collected to help diagnose the issue. Please note that performance in general is not an easy issue to tackle. This is because it can be caused by many issues that may not be disk related. For example, a disk will perform as well as the applications ask of it. So, a slow application may misguide you to think that you have a disk performance issue.The best way in any troubleshooting method is to eliminate, as much as possible, the factors that can cause performance issues. For example, let us look at the layers involved in a simple UFS filesystem on a disk: Physical Disk. LUN if it is an array. Host Bus Adaptor. HBA Driver sd/sdd driver ufs driver application performing I/O to the filesystem. These are some of the layers involved in the path of a single I/O, yet it is not exactly comprehensive. In this post I'm expecting that you can read iostat outputs. Refer Iostat reading Step 1. Define the Problem. Generally a problem is identified when an application is not performing as expected.The above is a very general statement and the best method is to clearly define what is it that is not performing as expected and then work out if the expectation is a realistic one. For example if we have an Ultra SCSI disk then we would not expect a throughput of more than 20 Mbytes/Sec theoretically. Hence this is what is meant by expectation. We need a realistic expectation before we can continue.Now a theoretical value of 20 MB/s for Ultra SCSI is not what we would get in real life, so we need to leave some room for that as well. There is no guide on how much lower the actual throughput will be, this is also dependent on many factors such as I/O size and type. This is left to common sense, the theoretical value should be used as a guide. We also need to clearly define the problem.For example a good problem statement maybe: iostat shows high avsc_t (100 ms) when Oracle write performance is only 3MB/s (iosize 8k) on /oradata1 volume, expect 15 MB/s with lower avsc_t (<30ms) Note the above is specific to the type (write) of operation, iosize, and the actual volume that is experiencing the problem. We also stated the current level and the expected level of throughput