I am a user of swift,but i only know a little about it. Now i encounter a problem：in my product environment, there are ten machines as object server, 12 disk per machine, it is strange that one disk is uesed about 80%,but others only 40%.what is the reason of that ? Thanks
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I am not able to find maria DB recommended RAM,disk,number of Core capacity. We are setting up initial level and very minimum data volume. So just i need maria DB recommended capacity.
Appreciate your help!!!
Seeing that over the last few years Micro-Service architecture is rapidly increasing, and each Micro-Service usually needs its own database, I think this type of question is actually becoming more appropriate.
I was looking for this answer seeing that we were exploring the possibility to create small databases on many servers, and was wondering for interest sake what the minimum requirements for a Maria/MySQL DB would be...
Anyway I got this helpful answer from here that I thought I could also share here if someone else was looking into it...
When starting up, it (the database) allocates all the RAM it needs. By default, it
will use around 400MB of RAM, which isn’t noticible with a database
server with 64GB of RAM, but it is quite significant for a small
virtual machine. If you add in the default InnoDB buffer pool setting
of 128MB, you’re well over your 512MB RAM allotment and that doesn’t
include anything from the operating system.
1 CPU core is more than enough for most MySQL/MariaDB installations.
512MB of RAM is tight, but probably adequate if only MariaDB is running. But you would need to aggressively shrink various settings in my.cnf. Even 1GB is tiny.
1GB of disk is more than enough for the code and minimal data (I think).
Please experiment and report back.
There are minor differences in requirements between Operating system, and between versions of MariaDB.
Turn off most of the Performance_schema. If all the flags are turned on, lots of RAM is consumed.
20 years ago I had MySQL running on my personal 256MB (RAM) Windows box. I suspect today's MariaDB might be too big to work on such tiny machine. Today, the OS is the biggest occupant of any basic machine's disk. If you have only a few MB of data, then disk is not an issue.
Look at it this way -- What is the smallest smartphone you can get? A few GB of RAM and a few GB of "storage". If you cut either of those numbers in half, the phone probably cannot work, even before you add apps.
MariaDB or MySQL both actually use very less memory. About 50 MB to 150 MB is the range I found in some of my servers. These servers are running a few databases, having a handful of tables each and limited user load. MySQL documentation claims in needs 2 GB. That is very confusing to me. I understand why MariaDB does not specify any minimum requirements. If they say 50 MB there are going to be a lot of folks who will want to disagree. If they say 1 GB then they are unnecessarily inflating the minimum requirements. Come to think of it, more memory means better cache and performance. However, a well designed database can do disk reads every time without any performance issues. My apache installs (on the same server) consistently use up more memory (about double) than the database.
I have developed a program which uses SQLite 3.7 ... database, in it there is a rather extensive write/read module that imports , checks and updates data. This process takes 14 seconds on my PC and Im pleased as punch with the performance.
I use transactions for everything with paratetrs my PC is a Intel i7 with 18gig of ram. I have not set anything in the database. I used SQLite Expert to create the database and create the data structures including table and columns and checked that all indexes are created. In other words its all OK.
I have since deployed the program/database to 2 other machines. That 14 second process takes over 5 minutes on the other machines. Same program, identical data, identical database. The machines are upto date, one is a 3rd gen Intel i7 bought last week, the other is quite fast as well so hardware should not be an issue.
Im just not understanding what the problem could be? Is it the database itself ? I have not set anything other then encription on it. Remembering that I run the same and it takes the 14 seconds. Could it be that the database is 'optimised' to my PC ? so when I give it to others its not optimised?
I know I could turn off jurnaling to get better performance, but that would only speed up the process and still would leave the problem.
Any ideas would be welcome.
EDIT:
I have tested the program on my 7yo Dual Athelon with 3gig of ram running XP on HDD, and the procedure took 35 seconds. Well in tolerable limits considering. I just dont get what could be making 2 modern machines take 5 min ?
I have an idea that its a write issue, as using a reader they are slower but quite ecceptable.
SQLite speed is affected most by how well the disk does random reads and writes; any SSD is much more better at this than any rotating disk.
Whenever changes overflow the internal cache, they must be written to disk. You should use PRAGMA cache_size to increase the cache to more than the default 2 MB.
Changed data must be written to disk at the end of every transaction. Make sure that there are as many changes as possible in one transaction.
If much of your processing involves temporary tables or indexes, the speed is affected by the speed of the main disk. If your machines have enough RAM, you can force temporary data to RAM with PRAGMA temp_store.
You should enable Write-Ahead Logging.
Note: the default SQLite distribution does not have encryption.
I have installed PostgreSQL 9.1 server on my production server.
I have Changed all the configuration(postgresql.conf) according to system.
Everything has been working fine for a week.
After this suddenly, postgresql server becomes very slow.
Even for count(*) query on a table.It is taking too much time.
After this I have done so many activities like:
Monitor Load on system :- Normal within range of 0.5 to 1.5.
Monitor No of users logged in application :- 200 to 400. Normal
Recreated Index
Kill the ideal transactions.
Check Locks (No DeadLock Found)
Application server restarted.
Database server restarted.
After doing this all activities the performance of database server is not increased.
It is taking so much time for normal queries also.
Then I drop the database and recreated then Performance Increases
Everything working after recreating the database.
But after some days suddenly performance goes down.
This sounds like the active portion of the database is growing large enough that it doesn't fit in cache, causing actual disk access (which is orders of magnitude slower) for many of your reads. This is often caused by not vacuuming aggressively enough.
Other factors could be related to your configuration of PostgreSQL and the operating system. It's hard to give much advice without knowing:
exactly what version of PostgreSQL you're using (9.1 tells us the major release, but the minor release sometimes matters),
how you have PostgreSQL configured,
what OS you're running on,
what hardware you are using (cores, RAM, drive arrays, controllers), etc.
Part of that can be supplied by posting the results of running the query on this page:
http://wiki.postgresql.org/wiki/Server_Configuration
It might also help to select relname, relpages, and reltuples from pg_class for the tables involved and compare numbers when things are running well to when they are slow.
With the additional information, people should be able to make some pretty specific recommendations.
I'm running a Windows 2008 server (a VPS with 1GB of RAM), with SQL Server Express and IIS 7 installed. On it I'm hosting a NopCommerce 1.7 website, with a database of around 26 000 products.
Right now I'm the only user of the website (it's in development) and I'm getting rather bad performance from it. To be more specific every time I make a request, the worker process goes to 90-100% CPU usage for a few seconds. Is it me or this is a lot for a 1 user NopCommerce website? Any ideas why this happens and what I can do to rectify it or further investigate?
PS: the worker process uses between 100MB-400MB of memory (private working set), and SQL Server with this database, around 160MB. Do you have any suggestions other then the obvious one to get more RAM? I intend to get one more GB but I fear this will not solve the cpu usage problem.
You've already stated you're going to get more RAM, but don't be surprised how much a lack of RAM can impact the CPU. If your RAM is not able to hold large objects efficiently because of lack of space (and I'd say using 40% of available RAM qualifies), then the CPU has to work harder to page things in and out of virtual memory. 90% is a little overkill for this, but with the server specs you give it's not impossible.
The most likely problem is that there is a hole in your code somewhere. My guess is that you have either an infinite loop or a direct memory leak (resources open during requests that aren't closed perhaps?). Your best bet would be to get the IIS Debug Diagnostics tool, install it and set up reports to find out what is going on directly on the server.
Environment:
Windows 2003 Server (32 bit); IIS6, ASP.NET 2.0 (3.5); 4Gb Ram; 1 Worker Process
We have a situation where we have a very large System.XmlDocument is being loaded into memory, and then it heads into a complied XSL transform.
What is happening is when a web request comes in the server is sitting in an idle state with 2500Mb of available system memory.
As the XML DOM is populated, the available memory drops approx 500Mb at which point we get a System.OutOfMemoryException event. At this point the system should theoretically still have 2000Mb of available memory available to service the request (according to Perfmon).
The related questions I have are:
1) At what level in the stack is this out of memory limitation being met? OS? IIS? ASP.NET? worker process? Is this a per individual web request limit?
2) Is this limit configurable somewhere?
3) Why can’t this web request access the full available system memory?
1) I would guess at the worker process but this should be configurable within IIS to the limit of memory that a worker process can use. Another factor is what level of bits does your software use, e.g. 32 bit has a physical limit of 4 GB since this is the total address space.
2) Probably but don't forget that memory fragmentation may play a role in getting to out of memory faster than you think, e.g. if there is a memory request for a contiguous 1000 Mb piece of memory then this may not necessarily be found in the current memory.
3) Have you examined dump data to see what is in the memory when the exception gets thrown? If not, there are ways to get a snapshot of the memory to see what it looks like as this may give you more clues about what is going on.
You are running in a process. A process can only access 2 gigs of memory. This task is sharing memory with everything else running in this process, so this bit of code does not get the full 2 gig -- even if it is available.
There is a 3 gig switch on the os as well. I believe it is a registry setting. But you will have to search MSDN to find that info.
But realistically, you need to do this another way. Possibly by switching to a SAX style xml parser.
I'm sure there are some bright heads here that can answer your specific questions, but have you asked yourself if there is another way to do what you want? I specifically mean that you probably do not want to process a very large XML document, but you probably more specifically want to return something back to the client. Could you rewrite the code to avoid this XML document altogether, or perhaps not load it all into memory at the same time, and still produce the same end-result?
1) Dunno. Check your logs.
2) IIS limits memory divvied out to websites/application pools. Check your settings.
3) Servers are all about uptime; if an single app hogs all the resources everybody else suffers. Thats why enterprise apps like IIS limit memory to prevent runaways from taking down the entire server.