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Registered: 06/08/06
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#173733 - 01/15/07 08:28 PM
Re: Server Crashing
[Re: Gizmo]
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Pooh-Bah
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Registered: 07/21/06
Posts: 2199
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In general only 1 gig of RAM is pretty light for as large an installation as you have. If you're only using but half of that gig you're not doing your server or it's discs a favor. All of that extra unused RAM could and should be used for database caching. More memory cache less disc access. As for why your machine becomes unresponsive we likely cannot tell you unless we're there to see it, but experience can be helpful. Here's the most common scenario that I've seen - Machine is either low on resources or isn't using them well but hums along just fine until something is done that brings it close to the edge of it's limits. Maybe it's a bunch of searches all at the same time, maybe it's a huge cache rebuild that occurs while a search is being run. Whatever the exact cause, it was a combination of things that brought a machine close to it's max out put. Now the machine is slowed and requests start to back up. Perhaps it's disc IO that is the culprit. memory use while the machine is backing up still looks fine. Load, while rising isn't huge. That's because the discs are so backed up nothing is being processed. Load is climbing though because of the number of processes that are waiting for disc. Doesn't take but a few seconds in that state to get a locked up server. Nothing is going to fix it now except a reboot. Do I know if that is what happened to your machine? No. But I wouldn't be surprised at all. I see it every day. You've got a gig of RAM, which is light for your volume, and only half of that is in use. Just think how much better the thing would run if it was making efficient use of the entire gig of RAM? Go here and read the tuning tutorials. A gig likely isn't enough for your traffic by why have a gig of RAM if you're only using half? Get that machine making more efficient use of your RAM and it will help. Of course, I'm taking your word that it is only using half the gig. That in itself sounds kinda fishy to me. Do yourself a favor and verify that again before you make any changes to your MySQL.
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#174846 - 01/21/07 12:12 PM
Re: Server Crashing
[Re: BellaOnline]
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addict
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Registered: 06/12/06
Posts: 515
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An update, the server crashed Friday night. They rebooted it Saturday morning. It crashed again Saturday night, and they rebooted it Sunday morning. On Monday they are going to add in a third hard drive to handle all the log files, to see if that helps. Intriguingly, MailEnable (the only other application on this server) reported errors during the crash time period. It says - ----------- 21 Jan 2007 00:07:05 MailEnable MailEnable Database Provider error: 0,FAILURE: (SELECT ID,Mode,AddressMask,Status,Account,AccessRight FROM SMTP_ACCESS WHERE ((Mode = 1) AND ((AddressMask = '64.*.*.*') OR (AddressMask = '64.74.*.*') OR (AddressMask = '64.74.173.*') OR (AddressMask = '64.74.173.203')) AND (AccessRight = 'CONNECT') AND ID > 0) ORDER BY ID LIMIT 1;), Module: MESMTPC.EXE; Error: [MySQL][ODBC 3.51 Driver][mysqld-4.1.16-nt]MySQL server has gone away 21 Jan 2007 08:33:55 MailEnable MailEnable Database Provider error: 0,FAILURE: (SELECT ID,Name,Status,Account FROM POSTOFFICE ORDER BY Name;), Module: MERADMS.exe; Error: [MySQL][ODBC 3.51 Driver][mysqld-4.1.16-nt]MySQL server has gone away ----------- So where did MySQL go? 
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#175668 - 01/26/07 01:30 PM
Re: Server Crashing
[Re: David Dreezer]
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addict
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Registered: 06/12/06
Posts: 515
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But again, there is plenty of RAM free. I'm running the SQL Administrator and it says the server is only being 5% used. All the cache hits seem great. Here are my settings - what do you think is set incorrectly? I'm a database designer and have done a ton of work with MS-SQL, Oracle etc - this forum system really isn't that big at all ... --------------- # The maximum amount of concurrent sessions the MySQL server will # allow. One of these connections will be reserved for a user with # SUPER privileges to allow the administrator to login even if the # connection limit has been reached. max_connections=800 # Query cache is used to cache SELECT results and later return them # without actual executing the same query once again. Having the query # cache enabled may result in significant speed improvements, if your # have a lot of identical queries and rarely changing tables. See the # "Qcache_lowmem_prunes" status variable to check if the current value # is high enough for your load. # Note: In case your tables change very often or if your queries are # textually different every time, the query cache may result in a # slowdown instead of a performance improvement. query_cache_size=33M # The number of open tables for all threads. Increasing this value # increases the number of file descriptors that mysqld requires. # Therefore you have to make sure to set the amount of open files # allowed to at least 4096 in the variable "open-files-limit" in # section [mysqld_safe] table_cache=1520 # Maximum size for internal (in- memory) temporary tables. If a table # grows larger than this value, it is automatically converted to disk # based table This limitation is for a single table. There can be many # of them. tmp_table_size=16M # How many threads we should keep in a cache for reuse. When a client # disconnects, the client's threads are put in the cache if there aren't # more than thread_cache_size threads from before. This greatly reduces # the amount of thread creations needed if you have a lot of new # connections. (Normally this doesn't give a notable performance # improvement if you have a good thread implementation.) thread_cache_size=38 #*** MyISAM Specific options # The maximum size of the temporary file MySQL is allowed to use while # recreating the index (during REPAIR, ALTER TABLE or LOAD DATA INFILE. # If the file-size would be bigger than this, the index will be created # through the key cache (which is slower). myisam_max_sort_file_size=100G # If the temporary file used for fast index creation would be bigger # than using the key cache by the amount specified here, then prefer the # key cache method. This is mainly used to force long character keys in # large tables to use the slower key cache method to create the index. myisam_max_extra_sort_file_size=100G # If the temporary file used for fast index creation would be bigger # than using the key cache by the amount specified here, then prefer the # key cache method. This is mainly used to force long character keys in # large tables to use the slower key cache method to create the index. myisam_sort_buffer_size=64M # Size of the Key Buffer, used to cache index blocks for MyISAM tables. # Do not set it larger than 30% of your available memory, as some memory# is also required by the OS to cache rows. Even if you're not using # MyISAM tables, you should still set it to 8-64M as it will also be # used for internal temporary disk tables. key_buffer_size=256M # Size of the buffer used for doing full table scans of MyISAM tables. # Allocated per thread, if a full scan is needed. read_buffer_size=1M read_rnd_buffer_size=4M # This buffer is allocated when MySQL needs to rebuild the index in # REPAIR, OPTIMZE, ALTER table statements as well as in LOAD DATA INFILE # into an empty table. It is allocated per thread so be careful with # large settings. sort_buffer_size=4M key_buffer = 256M max_allowed_packet = 1M
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#175746 - 01/26/07 07:43 PM
Re: Server Crashing
[Re: Rick]
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Registered: 06/05/06
Posts: 14904
Loc: Portland, OR; USA
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#175760 - 01/26/07 08:06 PM
Re: Server Crashing
[Re: Mark S]
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Registered: 06/05/06
Posts: 14904
Loc: Portland, OR; USA
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#175764 - 01/26/07 08:11 PM
Re: Server Crashing
[Re: Gizmo]
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Registered: 06/08/06
Posts: 1437
Loc: NY
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