Jacek,
----- Original Message ----- From: "Jacek Becla" <[EMAIL PROTECTED]>
Newsgroups: mailing.database.myodbc
Sent: Friday, November 12, 2004 2:30 AM
Subject: scalability of MySQL - future plans?
Hello,
What are the plans regarding improving scalability of MySQL? We are
currently trying to decide what technology/product to use for a large
project that will generate ~600TB/year starting in 2012. Any pointers to
related articles or hints how safe is to assume that MySQL will be able
to handle petabyte-scale dataset in 8-10 years would be greatly appreciated.
hmm... this mostly depends on hardware. With the innodb_file_per_table option, a single InnoDB table can be 64 TB in size, and you can have 4 billion such tables.
With current PC hardware, the speed of a single CPU allows you to insert 10 000 rows per second, if the load is not disk-bound. Let us assume that a single row in 100 bytes. That makes 1 MB/s, which is 30 TB/year. CPU speed will probably double every 4 years or so. Thus, CPU speed will suffice if you use a multiprocessor.
Normally, a database server has main memory at least 1 % of the data size. Is 6000 GB RAM realistic in 2012? Memory sizes will probably double every 2 to 3 years. If a high-end server today has 32 GB of RAM, in year 2012 it might have 512 GB of RAM. You will need a huge server.
The worst problem is the disk seek time. If your tables have secondary indexes where the insertion order is random, a modern disk, in combination with the InnoDB insert buffer, can insert maybe 200 random records per second. That is 100 rows/s for a typical table. You are going to insert 200 000 rows/s. You may need a disk farm of 4000 physical disks. Such disk farms exist today, but they are expensive, and we have no experience how Linux performs on them. Probably by 2012, Linux is good enough, if not yet today.
If you insert rows in large batches to tables smaller than your main memory, or if you insert in the prder of the primary key, and you do not have secondary keys, then there are no random accesses to disks, and you do not need a disk farm.
A typical disk in 2012 may store 1 TB. Thus, you will need at least 600 disks anyway.
How long does it take to build an index to a 64 TB table if you have 6 TB of memory? If the index completely fits in the memory, then this is sequential disk I/O. With today's high end disks, you can read 60 MB/s. Building an index with a single disk would take 2 weeks. In 2012, it might take only 3 days.
Conclusion: MySQL/InnoDB is able to handle that workload of 600 TB/year in year 2012. But you will need a huge server which has 10 x the memory of a high-end server, and 600 - 4000 physical disk drives.
The following link describes a system with 512 GB of memory, and 2000 disk drives:
http://www.tpc.org/results/individual_results/IBM/IBM_690_040217_es.pdf
The system costs 5.6 million US dollars.
Best regards, Jacek Becla Stanford University
Best regards,
Heikki Tuuri
Innobase Oy
Foreign keys, transactions, and row level locking for MySQL
InnoDB Hot Backup - a hot backup tool for InnoDB which also backs up MyISAM tables
http://www.innodb.com/order.php
Order MySQL technical support from https://order.mysql.com/
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