Questions tagged [disk-structures]

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Moving MySQL databases/folder to another disk

I want to separate MySQL database from the OS (Ubuntu) disk by moving the entire database to an exclusive HDD (M.2), and update the database folder in my.cnf. My question is: when the MySQL folder is ...
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22 views

disk cluster in SQL server 2017 [duplicate]

Still, as for older SQL servers, all disks should be formatted with a 64kB cluster disk, except for a system disk that is at 4kB? The discussion on the Internet differs on this issue. Thank you for ...
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1answer
79 views

Is postgres vacuum secure

Postgres delete doesn't actually remove the record from the table file. Once the delete is committed and the last transaction is closed, no postgres process can see the record any more, the deleted ...
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3answers
386 views

Does Index Rebuild Reduces physical read from disk

Recently I have rebuild indexes uisng Ola Hallengreen script which were 99% fragmented. After rebuilt i have noticed the physical reads have reduced a lot. Does this has anything to do with Index ...
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0answers
26 views

How a single column update is saved to disk

In learning about how data in a database is saved to disk, I came across the slide below. Earlier in the presentation they mention a block size is roughly 512 to 8,192 bytes. I haven't worked with ...
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1answer
182 views

How to Store Skip Lists on Disk

I am new to thinking in terms of databases. I have read about how B-trees are stored on disk but I haven't seen an actual implementation or read about how it works for B-trees. Wondering how one ...
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1answer
53 views

How Database Formats Files for Disk

This SO answer outlines how MySQL organizes its database into files, but doesn't describe the structure of the files themselves. I am wondering, at the physical level, how relational database ...
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2answers
10k views

How to create a flexible table schema for storing messages from different chats?

Help please solve the following situation: There are two kinds of API where message history is stored, it's Zopim and Chat2Desc (import into Postman). While these two but can then others appear. And ...
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1answer
198 views

Which hard disks for PostgreSQL? [closed]

The size of the our PostgreSQL data directory is 100 GByte. Up to now we use traditional hard disk drives and hardware RAID 10. Which hard disk drives and RAID setup would give us maximum ...
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3answers
323 views

Configuring physical storage for a Microsoft SQL Server installation

I'm configuring a Microsoft SQL Server installation which will use a SAN for storage. For SAN storage I have: A small number of SSD disks A larger number of 10K disks My SAN supports storage ...
2
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1answer
233 views

Configuring Dynamics GP's (SQL Server) Disks

I am an accidental DBA at my work, and when I took it over, it was quiet a mess. Fortunately, we have the green light to build new systems for an upgrade to our accounting system: Microsoft Dynamics ...
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1answer
2k views

What is the number of disk cylinders in a disk? [closed]

A disk has the following characteristics : bytes per sector = 512 sectors per track = 50 tracks per surface = 2000 number of platters = 5 average rotational speed =5400 rpm average seek time = 10 ms ...
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1answer
165 views

MDF, LDF, TempDb Location on same Hybrid SAN

I have seen this question asked before regarding SSDs or SANs, but never a Hybrid SAN. Also, most of the questions are several years old, so I figured I'd get a fall 2016 take on the answer. We ...
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1answer
203 views

Log Shipping Disk Sizes

Do the drives that contain the database have to be the exact same size on the primary server as secondary? I currently have a primary database for OLTP and a standby database used for reporting. I'm ...
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2answers
679 views

MongoDB aaS - administrate volumes/disk size - consequences of full volume - new file allocation failure

We run MongoDB (currently 3.0.6) as a Service. MongoDB is running inside Docker Container with a small volume 8 GB where mongod data files are stored permanent. The volume can't be extended. This is ...
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1answer
51 views

Database engine disk access [closed]

Do you know what is the difference between the database engine get rows in a table without and with use of an index in a disk prespective. They way the engine access the table in disk is the same when ...
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3answers
7k views

Understanding Disk Partition Alignment for Windows Server 2012 and SQL Server 2014

I am about to setup a SQL Server 2014 on a Windows Server 2012. Starting from best performance on the drive I formatted the drive with 64k allocation unit size. Now I am stuck using Diskpart to set ...
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2answers
6k views

RAID10 vs. RAID5 for data files

We are trying to evaluate the potential performance improvements that could be gained by switching an existing applications .mdf files to a RAID10 LUN vs. the existing RAID5 LUN they are living on ...
2
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1answer
529 views

Why do/should DBMS cache at the application layer?

This article describes DBMS as caching data at the application layer, which is why they often use Direct IO to bypass the file buffer cache. My question is: what benefits are provided by the DBMS ...
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0answers
489 views

Is my SQL Job causing the High Disk usage?

I have a concern regarding High Average disk queue length for one of my server with below configuration: Version: SQL 2005 with SP3, standard edition. windows: version 2003 r2 SP2 No Processors= 4 ...
2
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1answer
7k views

Can you put a SQL DB on a NAS? [closed]

Can you put a SQL DB on a NAS drive? For example can I put the PostgreSQL DB "files" on a Sinology NAS or am I better to leave everything on a "real" PC? (like, say, a regular PC server running Linux) ...
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1answer
60 views

What makes yum difficult with RAID [closed]

I as working with someone on a redhat server using RAID 10 with MySQL, and they mentioned it is hard to use yum when having a raid setup. Is this true? If so, what actually makes it 'difficult'?
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2answers
360 views

RAID Storage Technology Outdated? [closed]

I am working on designing requirements for new SQL Server installation. I have been researching disk storage and everything seemed to point to using RAID. However, I found this article, which ...
2
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1answer
916 views

Does Windows Server File Compression slow Oracle DB performance?

I'm starting a new a new contract and I get to troubleshoot their Oracle instance... I'm more apps and sql, but I'll be trying to figure out their crashes and slow performance. Go figure. I can ...
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1answer
104 views

Disk page size for MySQL and MySQL cluster [closed]

As I know database reads data from disk in some constant page size (even if one byte is needed, whole page will be copied from disk to memory). What are disk page sizes for MySQL and MySQL Cluster? Is ...
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1answer
6k views

SQL Server 2012 Express fails at repair install, produces error 5178

My SQL Server Express Service will not start up. To produce this problem, I basically cloned my old hard drive (Which had SQL Server Express 2012 installed) to a new hard drive (Seagate Momentus XT ...
4
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2answers
11k views

Change drive letter (which contains system dbs)

Is it possible to safely change the drive letter for a volume which holds only system databases? What precautions should be taken and how should it be done? I know I can just go to computer ...
3
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1answer
808 views

How un-clustered is a CLUSTER USING table in PostgreSQL

I have some tables which benefit greatly from CLUSTER ON/CLUSTER USING in Postgres SQL: # CLUSTER table USING index_name; # ANALYZE VERBOSE table; # CLUSTER VERBOSE; A maintenance task periodically ...
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2answers
10k views

Splitting TempDB into multiples files equal to number of CPUs

The article SQL Server tempdb Best Practices Increase Performance suggests that I should split tempdb into a number of files equal to the number of cores. So for 4 cores you get 4 files. By having ...
8
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2answers
1k views

How should I configure these disks on a SQL Server for a BI configuration?

Assuming constant memory (32gb) and CPU (4), 2 x disk arrays, I have the following disks 2 x 150 (10k) 6 x 150 (15k) They are all local disks. My requirements My DB is 350gb and set to default 10% ...
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1answer
15k views

Understanding block sizes

My question targets Postgres, but answers might just be good enough coming from any database background. Are my assumptions correct: Disks have a fixed block size? RAID controller can have a ...
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4answers
7k views

Can I specify a different disk for a specific MySQL table?

I use my home machine as my personal database for my hobby analytics project. This machine has an SSD for the main drive where MySQL stores its data. It also has a secondary hard drive that is ...
11
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4answers
6k views

Help me choose a RAID level combination for a SQL Server 2008 instance

I am going to rebuild one IBM 3400 server from scratch. This server is dedicated to a SQL Server 2008 instance running on Windows 2008 R2. I am going to make new RAID configuration. I have 6 SCSI ...
3
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1answer
175 views

Extreme storage beasts

Intro I have derived this question from my previous question Single Drive vs Multiple Drives After getting a very detailed answer from a very helpful member RolandoMySQLDBA and learning the fact that ...
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2answers
2k views

Single Drive vs Multiple Drives

Generally bottleneck of RDBMS (I am a MySQL user) performance is disk access. SSD provides great performance compared with conventional spindle drives. Question : Is it possible to improve ...
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2answers
2k views

SQL Disk Setup Advice - TempDB, Log DB, Data file placement question

We have a very active database server with a ecclectic collection of applications running on it. Two of the busiest are a Laserfiche database that does document scanning and workflow processing all ...
3
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1answer
2k views

MySQL InnoDB data file directly on a disk slice (fixed-size)?

It seems that ibdata1 is like a disk slice. In Solaris (UNIX) UFS filesystems (the common one before ZFS), one would separate their disk c0t0d0 into slices, say a 10GB drive would be cut into three ...
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2answers
3k views

Unknown Db file format - best way to find out?

A client has given me the data he wants visualised in my project - but I don't know what DB format it's in. He's pretty unclear, also.. I have access to the table structures, but don't know how to ...
10
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3answers
1k views

SQL Server: filegroup for system tables only?

One of our corporate standards to is have a separate filegroup/file for user tables/indexes. This is set as the default so no need to qualify CREATE TABLE statements. So it looks like this fileid 1 ...