Physical Vs. Logical Disk Queue Length
Jun 16, 2003Does 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
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Calculating COUNTER Physical Disk: AVG. DISK QUEUE LENGTH
Sep 10, 2007If 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.
Avg Disk Queue Length
Aug 14, 2007avg disk queue length is 100%. Any ideas?
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How To Calculate AVG. Disk Queue Length
Sep 6, 2007Hi 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 - PLEASE HELP
Jul 17, 2007PROBLEM: 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
Should The Quorum Disk Be A Physical Disk Or Majority Node Set?
Nov 15, 2006Hello,
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
What Is Logical And Physical Database Design
May 19, 2008hi we are in the process of developing a project and we r at the initial phase i.e. at the analysis phase and we have been discusssing on what is physical and logical database design. can any body send any links or articals on this will be hightly appreciated.
View 1 Replies View RelatedDifference In Logical And Physical DB Schemas
Sep 12, 2005What is the difference between the logical database schema and the physical database schema?
Thanks!
Is There A Way To Change Logical And Physical Datebase Filenames?
Aug 23, 2006A database was set up as a test database and then the database name changed but the logical and physical filenames still have test in their name - obviously not a good idea. I have tried to change the physical file name but get the error message that the physical file name cannot be changed once the database has been created. I have also tried detaching the database and renaming the mdf and ldf files but these could not be re-attached so had to revert back to the original names.
View 2 Replies View RelatedSQL 2012 :: Difference Between Logical And Physical Join?
Jul 9, 2014What is the difference between Logical Join and Physical Join and there Types?
View 6 Replies View RelatedSQL Server 2008 :: Logical And Physical File Names Of All Databases
Apr 3, 2011Is there a query or sp that I can pull all databases on the server along with their logical file names and physical file names?
View 5 Replies View RelatedAnalysis :: Cube Extracting Data From Physical Or Logical Star Schema?
Oct 22, 2015We have an OLTP database and operational reporting is carried out on a replica server / database. We have plans to build a new data warehouse and an analysis services cube.
Question 1:Should a cube be designed to extract data from a physical star schema rather than a logical one (3NF relational (ODS?) using a data source view to derive the star)? I'm guessing for performance it's better to pull data from similar structures (physical facts and dimensions as required by analysis services) but is the difference significant?
Question 2:Depending on the answer to q1, is it bad practice to ETL data from a staging database (replica > staging) directly to a star schema (multiple data sources and cleansing / business rules required)? Or should it be processed from staging to an ods and only then to a star schema (physical or logical). I still don't know if an ODS is required but I guess the consideration for this decision is whether the business would require  daily operational (or ad hoc) reporting on the consolidated data sources (without needing historical DW functionality).
Physical Disk Partitions
May 21, 2007I 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/O Queue Length
Aug 2, 2007Running 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 RelatedMoving A Database To Another Physical Disk
Jun 7, 2006I 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?
Weird Physical Disk Access
Jan 28, 2004Hi,
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.
Move Log File To Another Physical Disk
Jul 13, 2007Hi 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
Avg Disk Queue Values
Nov 8, 2007Again 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?
SQL Performance - Disk Queue.
Oct 25, 2007
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
Network Output Queue Length
Mar 18, 2005On 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 RelatedFile Fragmentation And Disk Read Queue
May 16, 2008I 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?
Logical Modeling Vs Physical Modeling
Nov 5, 2006Can someone please explain this statement: At the logical level where there can be any number of entities in a relationship while physically you define relationships between two tables.
thx,
Kat
Is It Possible To Move My Sql 2000 Database (in C Disk) To Another Disk (Disk) ?
Dec 28, 2006hello,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!
Clarifications On Queue Service And Queue Readers
Jan 11, 2006Hello,
This is info that I am still not certain about and I just need to make sure, my gut feeling is correct:
A.
When a procedure is triggered upon reception of a message in a queue, what happens when the procedure fails and rolls back?
1. Message is left on the Queue.
2. is the worker procedure triggered again for the same message by the queue?
3. I am hoping the Queue keeps on triggering workers until it is empty.
My scenario is that my queue reader procedure only reads one message at a time, thus I do not loop to receive many messages.
B.
For my scenario messages are independent and ordering does not matter.
Thus I want to ensure my Queue reader procedures execute simultaneously. Is reading the Top message in one reader somehow blocking the queue for any other reader procedures? I.e. if I have BEGIN TRANSACTION when reading messages of the Queue, is that effectively going prevent many reader procedures working simultaneously. Again, I want to ensure that Service broker is effectively spawning procedures that work simultaneously.
Thank you very much for the time,
Lubomir
T-SQL (SS2K8) :: Procedure Parameter Length Declaration Less Than Column Length?
Jun 30, 2014is there any way or a tool to identify if in procedure the Parameter length was declarated less than table Column length ..
I have a table
CREATE TABLE TEST001 (KeyName Varchar(100) ) a procedure
CREATE PROCEDURE SpFindNames ( @KeyName VARCHAR(40) )
AS
BEGIN
SELECT KeyName FROM TEST001
WHERE KeyName = @KeyName
END
KeyName = @KeyName
Here table Column with 100 char length "KeyName" was compared with SP parameter "@KeyName" with length 40 char ..
IS there any way to find out all such usage on the ALL Procedures in the Database ?
BlobColumn.GetBlobData() With Data Length &&> Integer Length (32767)
Mar 27, 2008For those of you who would like to reference my exact issue, I'm dealing with the RSExecution SSIS package at the "Update Parameters" data flow task, at the Script Component.
The script tries to split parameter data into name and value. Unfortunately, I have several reports that are passing parameters that are very large. One example has over 65,000 characters all in the normal "¶mname=value&parm2=value..." format.
The code in the script works fine until it gets to one of these very large parameter sets. I have figured out what is causing the issue. Here's some code:
Dim paramBlob as Byte()
paramBlob = Row.BlobColumn.GetBlobData(0, Row.BlobColumn.Length)
The second parameter of the .GetBlobData function takes an INTEGER as its count! Therefore, no matter what kind of datatype I pass to the string that the script will later split, it will be limited to 32767 characters.
THIS IS A PROBLEM!!!
Does anyone know a workaround for this issue? I need all of the parameter data to be reported, and I would hate to have to skip over rows like this. Also, if I'm missing something, please fill me in!
Thanks for your help in advance,
LOSTlover
Get Total Disk Size And Free Disk Space
Nov 13, 2007-- 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"
CommandParameters.length Don't Match Parametervalues.length
Feb 24, 2008I am trying to narrow down this problem. Basically, I added 3 columns to my article table. It holds the article id, article text, author and so on. I tested my program before adding the additional field to the program. The program works fine and I can add an article, and edit the same article even though it skips over the 3 new fields in the database. It just puts nulls into those columns.So, now I have added one of the column names I added in the database to the code. I changed my businesslogic article.vb code and the addarticle.aspx, as well as the New article area in the addartivle.aspx.vb page. The form now has an additional textbox field for the ShortDesc which is a short description of the article. This is the problem now: The command parameters.length is 9 and there are 10 parameter values. Right in the middle of the 10 values is the #4 value which I inserted into the code. It says Nothing when I hover my mouse over the code after my program throws the exception in 17 below. Why is command parameters.length set to 9 instead of 10? Why isn't it reading the information for value 4 like all the other values and placing it's value there and calculating 10 instead of 9? Where are these set in the program? Sounds to me like they are hard coded in someplace and I need to change them to match everything else. 1 ' This method assigns an array of values to an array of SqlParameters.2 ' Parameters:3 ' -commandParameters - array of SqlParameters to be assigned values4 ' -array of objects holding the values to be assigned5 Private Overloads Shared Sub AssignParameterValues(ByVal commandParameters() As SqlParameter, ByVal parameterValues() As Object)6 7 Dim i As Integer8 Dim j As Integer9 10 If (commandParameters Is Nothing) AndAlso (parameterValues Is Nothing) Then11 ' Do nothing if we get no data12 Return13 End If14 15 ' We must have the same number of values as we pave parameters to put them in16 If commandParameters.Length <> parameterValues.Length Then17 Throw New ArgumentException("Parameter count does not match Parameter Value count.") 18 End If19 20 ' Value array21 j = commandParameters.Length - 122 For i = 0 To j23 ' If the current array value derives from IDbDataParameter, then assign its Value property24 If TypeOf parameterValues(i) Is IDbDataParameter Then25 Dim paramInstance As IDbDataParameter = CType(parameterValues(i), IDbDataParameter)26 If (paramInstance.Value Is Nothing) Then27 commandParameters(i).Value = DBNull.Value28 Else29 commandParameters(i).Value = paramInstance.Value30 End If31 ElseIf (parameterValues(i) Is Nothing) Then32 commandParameters(i).Value = DBNull.Value33 Else34 commandParameters(i).Value = parameterValues(i)35 End If36 Next37 End Sub ' AssignParameterValues38 39 40 41
View 2 Replies View RelatedDisk Crash Of Disk That Contains The Paging File.
Feb 20, 2001Hello,
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.
SQL Server, Disk Arrays And Disk IO
May 7, 2004Hi 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
Logical Name
Feb 13, 2008Hi all
We generally modify the logical name of a data file or log file from the vendor defined to our standard name. Is there any impact that you know about this? If you have 2 seperate database and accidently you have 2 same logical name .. I dont' think that will be an issue ... correct?
ALTER DATABASE XXX_UAT
MODIFY FILE (NAME = 'mdd_Data', NEWNAME = 'XXX_UAT_Data')
GO
ALTER DATABASE XXX_UAT
MODIFY FILE (NAME = 'mdd_Log', NEWNAME = 'XXX_UAT_Log')
GO
Logical Name
Jul 17, 2007Hi,I want to change the logical name of the database. My database name and.MDF has the same name, but the logical name is different. Willchanging it impact anything?--sharif
View 1 Replies View RelatedSQL Select And Logical OR
May 21, 2008I have a query. on my search page i have a number of textboxes e.g. title, subtitle, ISBN where users can enter a search string and when they click on a button the data is displayed in the gridview below.
my query seems to be bringing up the right records but with some additional records into the gridview. I have tried the same query within the SQL server management studio and it brings back two records like indicated but within my aspx page it brings back 6 additional records that have no relevance to the query. Im quite baffled as to why this is happening and i have debugged but nothing comes to light.
my code in my aspx page is as follows:
public void BindData(){String _BookID = TxtBookID.Text;String _Title = TxtTitle.Text;String _Subtitle = TxtSubtitle.Text;String _ISBN = TxtISBN.Text;String AuthorFName = TxtForename.Text;String AuthorLName = TxtSurname.Text;
SqlDataAdapter ad = new SqlDataAdapter("SELECT Book_ID, Book_ID_Internal AS [Book Internal ID], Title, Subtitle, ISBN, Edition, Publication_Date AS [Published Date] FROM Book WHERE Book_ID_Internal = '" + _BookID + "' OR Title = '" + _Title + "' OR Subtitle = '" + _Subtitle + "'", conn);DataSet ds = new DataSet();ad.Fill(ds, "Book");if (ds.Tables[0].Rows.Count == 0){//if there are no rows returned-state in the gridds.Tables[0].Rows.Add(ds.Tables[0].NewRow());GridView1.DataSource = ds;GridView1.DataBind();int columncount = GridView1.Rows[0].Cells.Count;GridView1.Rows[0].Cells.Clear();GridView1.Rows[0].Cells.Add(new TableCell());GridView1.Rows[0].Cells[0].ColumnSpan = columncount;GridView1.Rows[0].Cells[0].Font.Italic = true;GridView1.Rows[0].Cells[0].Text = "No Records Found";}else{GridView1.DataSource = ds;GridView1.DataBind();}}
if i input the same query into SQL management studio:
SELECT * FROM Book WHERE Book_ID_Internal = 'ITD 450' OR Title = 'HTML 4.0'
it returns two records which is correct.
Can anyone see where i am going wrong?