New answers tagged

3

Searching google for ping "us-mid" yields Monitis.com and their IP in Dallas, who also have a DE IP in Frankfurt. From a very well-connected server in France I have 9 ms ping RTT to the DE IP and 111 ms ping RTT to the US-MID IP. For HTTP time-to-response I'd expect double that plus the server's reaction time, for the sake of argument let's say maybe 26 and ...


6

Assuming the graph is http request time it seems fairly reasonable to me. A http request (in the absense of keepalive, fastopen etc) normally requires at least two round trips. Client sends syn Sever receives syn and sends syn-ack Client receives syn-ack and sends ack and request. Server sends response. The speed of light in fiber is about 2*10^8 ...


1

First, it is perfectly normal that DM devices does not have any I/O scheduler, as (with specific exceptions) About the low performance you recorded, consider that your H310 controller not only has no cache, but it even disables the physical disk's DRAM cache, meaning your system has no way to lower latency via caching. Combining that with encryption, where ...


13

Any other possible reason in addition to distance from server? The path the packets take.


0

I did some research and this is what I found on different forums: There are two possibilities: slow Office save times to Windows Server 2008 Vitaly suggested to disable SMB2 on the server that holds the share. To do so add a REG_DWORD entry named Smb2 with a value of 0 to: HKLM\System\CurrentControlSet\Services\LanmanServer\Parameters Then reboot the ...


0

0.90 seconds seems good to me you should not bother about it much. Still being paranoid you can increase the NIC card bandwidth for better performance.


2

The problem was https://developers.google.com/speed/pagespeed/module/ which have done cache clean every hour. Configuration it to store files on tmpfs fixed the problem.


-1

I was also facing the same issue until I fount out the root cause of the problem... Problem: Currently, my website is running on Wordpress with XAMPP on windows cloud server and the CPU usage is going 100% Solution: checked my Apache log file(access.log) and some one continuously was trying to access the xmlrpc.php file and 10 requests every seconds that ...


0

Maybe you have some MySQL scheduled events going on each hour? MySQL Events are tasks that run according to a schedule. Therefore, we sometimes refer to them as scheduled events. When you create an event, you are creating a named database object containing one or more SQL statements to be executed at one or more regular intervals, beginning and ...


1

Scientific Method is your friend. You or someone on your behalf will have to monitor your system to gather the necessary data to allow you to make an informed decision. Your load average spikes quite sharply and at predictable times, that means it should be fairly straightforward to monitor the event with tools like top, iostat, vmstat etc and start the ...


-2

you can use dd to mesure the latency of a disk eg. dd if=/dev/zero of=/root/testfile bs=512 count=1000 oflag=dsync


2

Random seek times will be roughly O(1) like uncompressed file systems as well, but with the caveat that up to 128 KiB of data is compressed together so to read just a single byte, all the data in that 128 KiB block will have to be read and decompressed. Depending on the access pattern, this can have a somewhat large performance impact, but you need to ...


0

Just to add one additional use of this setting: it is needed by xperf stack walking. http://blogs.msdn.com/b/pigscanfly/archive/2009/08/06/stack-walking-in-xperf.aspx Disable Paging Executive In order for tracing to work on 64-bit Windows you need to set the DisablePagingExecutive registry key. This tells the operating system not to page kernel ...


0

Just to add to this, some Solaris specific tools which haven't been mentioned which are useful in debugging such issues are "intrstat", "mpstat" and "lockstat". Having experienced a similar issue before on a host running some heavy ETL loads mpstat revealed a high amount of interrupts dealing with lots of I/O which hinted at the issue. At the time, on a T4-...


0

If your confident that your server will not be using more than 15G of RAM, (really 12-13G for breathing room would be better), then you could always disable swapping all together. Swap space was created due to the high costs of RAM in the past. Personally, I've disabled swapping on most of my Linux machines with no issues so far, and one of them only has ...


0

The answer is no, the backplane isn't going to be a limiting factor. From Dell's technical guide for the PowerEdge R610 (http://www.dell.com/downloads/global/products/pedge/en/server-poweredge-r610-tech-guidebook.pdf) I cannot find anything to do with backplane negotiation speeds. In my experience working with servers, even on lower end SuperMicro servers ...


0

You can dump disk activities (along with the pid generating it) in syslog with the following command: echo 1 > /proc/sys/vm/block_dump Before issuing this, make sure that your system logs aren't on a block device, otherwise you'll end up in an infinite loop.


0

Providing a proper answer to your question goes way beyond the scope of a post here - it's way too broad. But the conclusion would be the same - assuming that redundancy is irrelevant, then the difference will depend on the nature of the workload (although as Andrew points out, it's a lot easier to mis-configure a RAID system than a single disk filesystem). ...


1

Recommended disk format size in Azure for any type of disk is 64K not 4K. This is due to the network nature of how storage is delivered to the VM. Try your tests with 64K.


1

There are some limits in Azure Premium Storage that you should consider to get optimal performance. In particular as you can see here there are IOPS and Throughput limits per premium disk. And they are different for different disk types. Moreover there are some limits per VM Size. So for the best result you should choose right VM Size, disk type and number ...


1

I am installing a 48T Dell MD-1200 and I was curious about this question. The MD1200 is connected to a hardware RAID card set up as RAID-6, so it looks to Linux like just a (big) drive. I tested an XFS filesystem on an LVM physical volume vs. an XFS filesystem on a straight disk partition. I used a Dell R630 machine with two E5-2699 CPUs in it. The system ...


0

Based on my experience, the CXPACKET was always the tricky wait type for younger DBAs that often caused some predictably wrong reactions. I've tried in Troubleshooting the CXPACKET wait type in SQL Server article to present most of the reasons for high CXPACKET but also to explain the CXPACKET background So for those who don't want to get in details, I will ...


2

You did not specified the vdisk cache type, so libvirt is assuming the most safest cache scheme: directsync, which imply that all writes are immediately synched to the physical disk. Such restrictive cache type is generally overkill for modern, cache-aware application, which uses write barriers by themselves to ensure important writes are synched to disk. ...


0

If you add the following line to your config file, it will stop IPv6 which slowed down my squid connections. tcp_outgoing_address 0.0.0.0 all


0

Use tools.pingdom.com This will tell you where your site is slowing down, then try to fix that using the plugin. Google also has https://developers.google.com/speed/pagespeed/insights/ that will also give you some information as to how you can increase server speed. Without actually seeing your site it will be impossible to know exactly what could be ...


2

Comparing the number of CPUs of a mainframe image isn't meaningful, most likely. Mainframes are designed to run multiple tasks at the same time, and give priority to whatever the business says is most important, and are capable of being very heavily virtualized, so looking at the number of CPUs doesn't tell you much. You have to understand the environment ...


1

First, this seems a common problem with DS213j and DSM 5.1+. Someone reported that after a reboot, the problem went away: have you tried it? From your top data, it seems that the CPU is busy with system time, ie: doing some syscall. Try changing the following parameters in the smb.conf file and then restart the NAS: change notify = no kernel change notify ...


0

I would suggest to either set the ignore_group_members option to true, or symlink the cache to tmpfs or wait for the 1.14 upstream release. The reason the group resolution is slow is that saving the group on cache update after the cache expiration always writes the full group object to the on-disk cache even if nothing had changed. In 1.14, we're changing ...


0

When using SAN storage, the filesystemio_options parameter setting should be reviewed. Setting the parameter to SETALL or ASYNCH alleviates log file sync waits during the truncate execution. On a busy system, running additional DB writers is recommended as well.


19

The recommendation from the Apache project is: In general, you should only use .htaccess files when you don't have access to the main server configuration file. ... a common misconception is that user authentication and mod_rewrite directives must go in .htaccess files. So please both set AllowOverride None and all your other directives in the main ...


1

I have tested with and without .htaccess and could really find no difference in speed or overhead whatsoever. Granted I only run 16 sites and it's a super fast server so in my case tracking milliseconds is almost impossible. On a server running hundreds of sites the overhead may be noticeable so as @Iain said test and see. I personally do everything using ...


1

I don't believe there is a single right answer for your question. Are many variables which can affect htaccess load time: Site folder structure: all .htaccess in each folders are loaded every time the page is open. How long is the htaccess file: 200 lines vs 3500 lines? there is a big difference. .htaccess configuration: rewrite and redirects rules can be ...


4

The expense depends upon how powerful the server is in particular it's storage I/O subsystem and whether there is any caching involved. The way to test it is to configure your system with .htacess and load test it in the same way as you would any web server. Then configure the system without .htaccess and run the same tests. Compare and contrast the ...



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