All customer sites will use the same application, but each will have its own set of 3 databases. In believe the nature of the application confines users to brief, bursty selects and updates except possibly when they run reports. I have not specifically analyzed reporting, but I ran a 2-hour sampling today of a client site with 25 users during a period of typical workload. Here's the overall disk statistics:
% Read Time: 5.26 % Write Time: 5.00 Avg Bytes/Read: 2918 Avg Bytes/Write: 6563 Avg Read Queue: .05 Avg Write Queue: .013 Avg Disk Secs/Read: .013 Avg Disk Secs/Write: .004 Avg Read Bytes/Sec: 15151 Avg Write Bytes/Sec: 66904 Avg Disk Reads/Sec: 3 Avg Disk Writes/Sec: 9 The numbers are very interesting. The system writes to disk 3 times more often than it reads, and the writes are more than double the size. Bytes written per second is 4 times higher than bytes read. Yet, on average, reads take longer than writes and they tend to stack up in the queue a little more, which could explain why % Read Time is slightly higher. This is a RAID 1 array. System has plenty of RAM and was not swapping. All in all, the application appears write-heavy, but I don't think anyone can hog all the disk I/O. So, your opinion is that one instance of MySQL with a lot of databases is just as efficient as multiple MySQL instances? (Note: I WILL have to run separate instances in some cases because some customers are using slightly different versions of the application.) --Eric -----Original Message----- From: Atle Veka [mailto:[EMAIL PROTECTED] Sent: Saturday, June 17, 2006 12:14 PM To: Robinson, Eric Cc: mysql@lists.mysql.com Subject: Re: MySQL Performance Question So, you're looking at 150-300 databases and ~31-62k tables based on your numbers? MySQL should be able to handle that, as should your OS, but the most important part IMO is how your clients will be using their data(bases). What sort of queries, how many, etc. Will it be possible for one client to hog all the disk IO? Ignoring the latter questions, with a properly designed database and tuned queries this doesn't seem like an impossible setup on a single database daemon. Atle - Flying Crocodile Inc, Unix Systems Administrator On Fri, 16 Jun 2006, Robinson, Eric wrote: > Our server will be home to 50-100 separate clients. Each client will > have their own set of databases that will be accessed by 10-60 users > at each client's site. > > In terms of performance, is it better to have 1 instance of MySQL > servicing multiple databases, or multiple instances of MySQL each > serving 1 database? > > Here's some more information to work with: > > Each client has 3 databases. > > Database: 500 tables. 13 tables sized 10-100MB. Remaining tables all > less that 10MB. (This is the only database that is updated. The others > are just for reference.) Main table grows at a rate of a few hundred > MB/year. > > Database2: 50 tables. 3 tables sized 10-100MB. All other tables less > than 10MB. No data growth. > > Database3: 179 tables. 10 tables sized 1-15MB. All other tables less > than 1MB. No data growth. > > --Eric > > > Disclaimer - June 16, 2006 > This email and any files transmitted with it are confidential and intended solely for [EMAIL PROTECTED] If you are not the named addressee you should not disseminate, distribute, copy or alter this email. Any views or opinions presented in this email are solely those of the author and might not represent those of Physician Select Management (PSM) or Physician's Managed Care (PMC). Warning: Although the message sender has taken reasonable precautions to ensure no viruses are present in this email, neither PSM nor PMC can accept responsibility for any loss or damage arising from the use of this email or attachments. > > -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
