If I return the Average, Minimum, and Maximum values for the counter Physical Disk: Avg. Disk Queue Length, and those values are 10, 0, 87 respectively, which value do I use to compute the Avg. Disk Queue Length for a 4 disk array(RAID 10): Average, Minimum, or Maximum? The disk(lun) is on a SAN.
Does anyone have any recommendation on whether it's better to monitor the average queue lenght for physical or logical drives? What about for a RAID set?
Just wondering,
thanks
avg disk queue length is 100%. Any ideas?
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http://www.sqlserverstudy.com
Hi All,
we have collected perfmon data for a specific lun. Here is the background of the lun. The lun is Raid10 with 4 physical disks. We have problems interpreting the data. In the perfmon counter screen we have a max of 435 and average of 0.512. Can somebody tell us what is that we are missing? Any help is greatly appreciated.
Thanks,
Venkat.
PROBLEM: Sporadic spikes in Avg. Disk Queue Length with users freezing up until it comes down.
Server:
-SQL Server 2000 SP4
-Windows Server 2003
-4 Intel Xeon Processors 5130 @ 2.00 GHz
-4 GB of RAM (SQL Configured Dynamically with min. of 0 and max. of 3072)
-Max Worker Threads – 255
Environment:
-100 users with about 65 on Thin Clients going through a Remote Desktop Server
-Front End CRM package is a program called Telescript
-I do not use replication or any triggers, mainly just scheduled DTS packages
-Largest and most heavily used Database is 13Gbs with using a fill factor of 80 on my indexes
Recent Changes – The most notable thing that I changed in the last couple of weeks as this problem arose was the SQL Mail function. I started using that and created some DTS packages that sent out emails. Our user base has been steadily growing, but nothing drastic.
So Far – The buffer cache hit ratio is good and I have not seen any problems with memory so that is ruled out. The processor time never maxes out, but it does appear to double when the Avg. Disk Queue Length spikes. I re-indexed my active tables and performed shrinks over the weekend, but the problem occurred yesterday again. Sometimes it will last under a minute, but the problem is really when it lasts for several minutes. I used SQL Profiler to try and identify what the query was causing the problem, and while I see some large audit times, I cannot tell what the problem is. I had a hard time reading through that with all of the Stored Procedures that were invoked (ie. cursor fetches). The server itself is very new and has only been in use for about 2 months, so I couldn’t imagine it would be hardware fragmentation.
QUESTION: What else should I be looking at or could I use to figure out where this problem is stemming from? I am in a corner and could use any suggestions as to diagnose this problem.
Thanks in advance,
Don
dkoehne@401kexchange.com
Hello,
I am trying to setup a test cluster and am having an issue. When I try to create the resource of a physical disk it takes both the drive e: and drive q: and doesn't seperate them into two physical disks as resources. This means when I try to associate the quorum disk it links the to physcial disk resource of drive e and q. Then when I try to install SQL2k5 I get the warning about installing SQL on the quorum disk. Am I missing something? Is there a way to seperate e and q onto two physical disk resources so I can specifically associate the quorum to q and the sql to e or should I be setting the quorum disk to a majority node set? Thanks in advance.
John
hello,all
I am new to Sql 2000,I installed sql 2000 database in C disk,but Now I found my C disk space is smaller than before,So I want to move my databse(include data and structure) from C Disk to D Disk(its space is very large) .
is it possible to do it ?
if its can be done ,do I need to change my asp.net program source code (exp: chaneg my crystal report connectstring ) ?
thanks in advanced!
I just inherited a dev box, and need to do some performance analyzing on a 40 gig db for a client. Time is of the essence!
My question is that this dev box only has one disk partition (c: drive). Is it a huge deal that I don't have the db system files on one drive, with the data files on another, and tempdb on another,etc.....
I want to move 2 databases to another physical disk. They are both single file databases. It looks like a fairly straigtforward attach and detach procedure, but I have a couple of questions:
The log files (.ldf) currently reside on a separate physical disk from the data files, if I attach and reattach the data files will the logs remain where they are by default or do I have to re specify there location?
Is there any advantage to running the update statistics portion of the sp_detach_db?
Hi,
I have an MS SQL 2000 server running on a Proliat with two CPUs and 2GB RAM (the process actually uses 1.6GB).
For some reason, the same queries (which return the same data) run sometimes very fast and sometimes very slow.
I used the performance counter to find out that when the queries run fast there is little disk i/o and when they run slowly there is a lot of i/o.
I thought it happens because the DB keeps swapping tables in and out of RAM. The problem is that these things happen in periods. I can have a few hours of slow access and then a few hours of fast access. This makes me believe that it doesn't actually put the table in the cache untill it is requested enough times. Very weird.
HELP?
Thanks.
Hi everyone,
Due to running out of disk space and reducing I/O contention, I plan to seperate data files and log files to different disk arrays.
My plan is to
- detach all databases
- copy log files to another disk
- attach all databases
The total size of log files is about 60GB. It becomes a problem becasue it spend too much time passing files. To reduce down time, is there any way I can do?
Can I just create new log files and remove the current files by using sql management studio?
any other suggestions? Thanks in advance
Again one client with SAN EMC and again performace is several times worse then you can have with a cheap and primitive IDE drive... :(
Anyway, my question.
I am monitoring many parameters, including Avg Read Queue and Avg Write Queue.
So if I ReadQueue=3 and WriteQueue=7, what does it mean?
Scenario 1, there are 2 different Queues (R- read request, W - write request):
Windows --> Device
Read. Queue: R:R:R
Write Queue: W:W:W:W:W:W:W
Scenario 2:
Windows --> Device
Common Queue: W.R.W.W.R.W.W.R.W.W
In other words, if SQL server flushes writes (TRAN COMMIT or CHECKPOINT), generating hundreds or even thousands of write requests in few milliseconds, so Queue grows to 100-300 for a second or so, are read requests locked during that time?
I am running SQL server 2000 SP4 on a server with 2 Dual core 4G processors with data attached via a SAN>
I have a 70G database with 10 users that is giving attrocious performance. I have just tried to run a count(*) accross a couple of tables and am still waiting for the results 15 mins later. When I look at the disk queue it is around 50/60. I thought the target for this was around 2. I am sure that the hardware that we have in place is capable of running this db. However I`m not sure how to fully analyse what is going wrong here.
Any tips would be greatfully received.
Si
We are collecting perfmon counters every 15 second . Among the counters is Average Disk sec/Write . I under stand that it is the average time taken in second to write a data to the disk. However I do not understand what the is quantum of data written in one second. What is the measure or unit  of data in Average Disk sec/Write or is it simply the average time taken for an I/O write request.
View 4 Replies View RelatedI have a poorly performing SQL box.
I have run perfmon and the avg read queue length is pretty much permanently maxed out at 100%.
I have run a database index defrag.
On further inspection the file system is highly fragmented. There is a file fragmentation of 98% with the mdf file fragmented in 25,000 pieces. Running a standard windows defrag does not resolve this.
Two questions?
1- Is heavy file fragmentation of the MDF file a likely cause of the read queue length bottlneck?
2 - Why is the MDF file not defragmenting? Does the SQL server have to be taken offline? Is it possible to defrag a MDF file?
-- Initialize Control Mechanism
DECLARE@Drive TINYINT,
@SQL VARCHAR(100)
SET@Drive = 97
-- Setup Staging Area
DECLARE@Drives TABLE
(
Drive CHAR(1),
Info VARCHAR(80)
)
WHILE @Drive <= 122
BEGIN
SET@SQL = 'EXEC XP_CMDSHELL ''fsutil volume diskfree ' + CHAR(@Drive) + ':'''
INSERT@Drives
(
Info
)
EXEC(@SQL)
UPDATE@Drives
SETDrive = CHAR(@Drive)
WHEREDrive IS NULL
SET@Drive = @Drive + 1
END
-- Show the expected output
SELECTDrive,
SUM(CASE WHEN Info LIKE 'Total # of bytes : %' THEN CAST(REPLACE(SUBSTRING(Info, 32, 48), CHAR(13), '') AS BIGINT) ELSE CAST(0 AS BIGINT) END) AS TotalBytes,
SUM(CASE WHEN Info LIKE 'Total # of free bytes : %' THEN CAST(REPLACE(SUBSTRING(Info, 32, 48), CHAR(13), '') AS BIGINT) ELSE CAST(0 AS BIGINT) END) AS FreeBytes,
SUM(CASE WHEN Info LIKE 'Total # of avail free bytes : %' THEN CAST(REPLACE(SUBSTRING(Info, 32, 48), CHAR(13), '') AS BIGINT) ELSE CAST(0 AS BIGINT) END) AS AvailFreeBytes
FROM(
SELECTDrive,
Info
FROM@Drives
WHEREInfo LIKE 'Total # of %'
) AS d
GROUP BYDrive
ORDER BYDrive
E 12°55'05.25"
N 56°04'39.16"
Hello,
this is my configuration :
1) 3 disks in RAID5 that hold the SQL data
2) 1 disk in RAID0 that holds the only paging file.
What will happen to the SQL data (DB) when the disk that holds the paging file crashes?
Kindest regards,
Luc.
Hi all,
Ok here goes,
I have a three tier system using SQL server 2000, we are currently experiencing IO bottle necks on our SCSI Raid 10 array, which holds the Data and the logs in separate partitions.
So my options as I understand it are:
Get Enterprise edition
or
Get another physical raid 10 array and separate the logs and data i.e. data on one array and logs on the other array.
I would like to try the latter but I am totally unsure how much difference this will make or whether it will make any difference at all.
Does anyone know how much performance increase I will get from using two arrays as opposed to one?
Any other advice on this scenario would be greatly appreciated.
Thanks
Running transactional replication, dedicated server for distributor. While performance in terms of latency is excellent (usually 1 sec, almost never higher than 4) the disk queue length on the distributor is extremely high (over 6 usually). Is this typical? On any other server I would be very concerned, but cpu and memory usage are excellent and as said, latency is good. what is recommended config for distributor? others see high queue length?
View 2 Replies View RelatedOn my busy sql server my network output queue length is a very large number 4343559902. My research shows it should be a < 2, but have also seen some bugs related to this perfmon counter. Anyone dealt with this issue before?
View 1 Replies View RelatedWe will move t-log from one disk to another one. I tried Alter Database and found it did not work for log.
Can somebody give me a method about moving log from different disks?
Thanks.
Jean
Hello
I need to setup a compaq sever with 300 MB database, and will be adding around 600 records on a daily basis. Can someone help with how much disk space i should have on sqlserver, providing i have c: and d: setup.
Thank you in advance for all the help.
Paula
Hi All,
I have a server and it has C: D: F: I: Drives and all the system files are on C:Drive and and all the .MDF's and .LDF's(model,temp,master) are on the F: Drive and now I am running out of space on both(C: and F: Drives)
1. Can we add space to the C: and F: drives on the fly?.
2. Can I move the System databases ( MDF's and LDF's to some other drive)and if so, how do I do it?( Moving the databases ) and this is on the production database so when I have to do this.Will there be any impact.
Thanks in Advance,
Reddy
Does anyone know how to get the free disk space for all drives in many different SQL servers.
I need to populate a report (right now output in Excel) with the free disk space of all drives on all of my SQL servers.
I found xp_fixeddrives but that is specific for the server where it is executed.
Any help or pointers to a script in the archives is much appreciated.
Thanks.
One of my production servers has been determined to be 92% fragmented.
What's the proper procedure for defraging a database server?
I couldn't find anything very helpful in BOL, nor Knowledge Base.
Sidney Ives
Database Administrator
Sentara Healthcare
We need a drive cloning app, like Ghost, that will allow us to transfer a production image off of a HDD to other PCs. The problem with this is that
our production needs SQL in order to run and transferring the initial image to uniquely named workstations causes DB registration problems. Is there
an app that will allow us to configure this transferred image so that SQL will refer to the "new" drive instead in of the "old"?
Hello,
We are experiencing high disk i/o on one of our RAID disk systems. Can someone tell me how I can identify the query or user or process which is causing this high disk i/o?
Thanks,
Brent.
I noticed something strange today. I was running a query using query analyzer on a large database (8.8 million records) and the disk space on the c: drive was dropping and eventually went to 0. Availalbe space on the c: drive is 10GB. The query did complete. SQL server and all the databases are on the d: drive. After closing the query results in query analyzer the disk space returned. Is this a concern and is there a way to change it to use the d: for whatever it is doing?
View 3 Replies View RelatedWhat's the best way to find out if disk fragmentation on Windows 2000 Server is affecting SQL Server performance?
If disk fragmentation is shown to be a cause of performance problems, what are the recommendations for a disk fragmentation strategy? eg. use the win 2000 built in disk defrag utility or buy a 3rd party product like DiskKeeper? How much of an overhead is a product like DiskKeeper that defrags in the background?
Clive
Hi all,
I have a problem...
I use SQL server 2000,all the disk on computer is used to store data file and transaction log file, and now they are full so data can be insert or update because the data file and transaction log file can be add more or increase, please show me.
Best regard,
I have one big db and i heve no place on disk
the log file is big too. how can i delete the log
This is my first attempt using SQL 2000 and DTS. I am importing an Access database using the DTS wizard. The process fails with a "Not enough space on temporary disk" error. There is definitely enough space on the physical disk. I don't have any limits on any folder sizes either. What "disk" is the error talking about, and how do I give it enough space. The database is relatively small, about 10MB. I believe the database was created using Access 97. Please help.
View 1 Replies View RelatedI understand the log files (LDF ) and data files (mdf ) should be on a different drives . I believe it leads to greater availabilty and speed . Are there any other reasons for to keep this on a separate drive.
Also what considerations I should take care while creating a database of around 100 GB . (use of filegroups , growth % etc ). Is there any connection of number of users to number of disks SQL data file to be spread to . Also do I need to take care (through hardware / software for a Quad core CPU ) to take full advanage of Quad core CPU.