SDS Posted May 6, 2010 Share Posted May 6, 2010 We currently have two 150GB 10k Raptor drives. One really just stores a nightly backup of the databases, etc... For the times that I need to turn off the "go to last read post" feature - it is because we are ultimately I/O bound and that feature writes the database on every *read* (beyond incrementing the views column), not just every write as one would expect. Because of this faster drives would help on super busy days... I was thinking of four 15k SCSI's in 10 RAID configuration. This would help with drive crashes and database speed I believe. Does anyone else have a conflicting or supporting opinion? Cost is about another $120/month I think - but perhaps it is well spent for data integrity and access speed. Link to comment Share on other sites More sharing options...
grammer_police Posted May 6, 2010 Share Posted May 6, 2010 We currently have two 150GB 10k Raptor drives. One really just stores a nightly backup of the databases, etc... For the times that I need to turn off the "go to last read post" feature - it is because we are ultimately I/O bound and that feature writes the database on every *read* (beyond incrementing the views column), not just every write as one would expect. Because of this faster drives would help on super busy days... I was thinking of four 15k SCSI's in 10 RAID configuration. This would help with drive crashes and database speed I believe. Does anyone else have a conflicting or supporting opinion? Cost is about another $120/month I think - but perhaps it is well spent for data integrity and access speed. What advantages of 10 RAID provide? I'm kind of a novice, but I know that it has to do with redundency, efficiency, and concurrency (any or all or more) Link to comment Share on other sites More sharing options...
ChasBB Posted May 6, 2010 Share Posted May 6, 2010 My understanding is that RAID 0 is fastest, but no so safe. RAID 1 is slow and RAID 5 is kind of slow, too. RAID 1+0 (RAID 10) is both fast and safe, but the tradeoff is higher disk utilization. More memory could maybe help, too. I don't know what kind of database you are running, so this may or may not apply, but with Oracle, for example, if you can give it a big enough chunk of memory, you can cache nearly your entire database in memory, thus improving your performance with disk I/O. Of course, it eventually must get written to disk, but that can happen with background processes and not impact real time performance. Link to comment Share on other sites More sharing options...
SDS Posted May 6, 2010 Author Share Posted May 6, 2010 My understanding is that RAID 0 is fastest, but no so safe. RAID 1 is slow and RAID 5 is kind of slow, too. RAID 1+0 (RAID 10) is both fast and safe, but the tradeoff is higher disk utilization. thanks, I understand those points. I'm sort of looking for "experience" type feedback. Link to comment Share on other sites More sharing options...
grammer_police Posted May 6, 2010 Share Posted May 6, 2010 My understanding is that RAID 0 is fastest, but no so safe. RAID 1 is slow and RAID 5 is kind of slow, too. RAID 1+0 (RAID 10) is both fast and safe, but the tradeoff is higher disk utilization. Oh... so does RAID 10 combine both data striping and redundency? And the tradeoff is the maintaince to keep the copies of disk in sync? Link to comment Share on other sites More sharing options...
outsidethebox Posted May 6, 2010 Share Posted May 6, 2010 thanks, I understand those points. I'm sort of looking for "experience" type feedback. Have you checked the tires? Link to comment Share on other sites More sharing options...
ChasBB Posted May 6, 2010 Share Posted May 6, 2010 Oh... so does RAID 10 combine both data striping and redundency? And the tradeoff is the maintaince to keep the copies of disk in sync? Yes, I believe so. It does mirroring for both redundancy and speed, so it takes up more of your disk space to store the same information. Link to comment Share on other sites More sharing options...
bladiebla Posted May 6, 2010 Share Posted May 6, 2010 thanks, I understand those points. I'm sort of looking for "experience" type feedback. Raid 10 does great with databases, have been doing that for about 12 years now and dont spec anything else anymore (unless I may spec ramsan or nas). Remember: more spindels = more performance (so if price wise it works out the same getting 6 smaller disks then get those). Link to comment Share on other sites More sharing options...
DarthICE Posted May 6, 2010 Share Posted May 6, 2010 From what I understand a RAID 10 outperforms a RAID 5 (the other viable option imho) at a fraction of the cost when it comes to read / write performance esp if you run a Lynux server. You get the Fault Tolerance of a RAID 1 combined with the speed of a RAID 0. I don't see how you can't not run this config Scott. Link to comment Share on other sites More sharing options...
Just Jack Posted May 6, 2010 Share Posted May 6, 2010 Cost is about another $120/month I think - but perhaps it is well spent for data integrity and access speed. You can always fix problems with more money. Link to comment Share on other sites More sharing options...
boyst Posted May 6, 2010 Share Posted May 6, 2010 SDS, not sure if you saw my post in the other thread about updating the wall, but I remember a long time ago seeing a thread about donating to help support TBD and TSW. Can we still help? I'm just poor folk but want to help support the cause! Link to comment Share on other sites More sharing options...
Booster4324 Posted May 6, 2010 Share Posted May 6, 2010 SDS, not sure if you saw my post in the other thread about updating the wall, but I remember a long time ago seeing a thread about donating to help support TBD and TSW. Can we still help? I'm just poor folk but want to help support the cause! Agreed, I want "Last Unread". I will chip in. Link to comment Share on other sites More sharing options...
mowisc Posted May 8, 2010 Share Posted May 8, 2010 We run our database servers with three channel cards. 15k Hot-pluggable drives. 1st channel is for the OS -- it's at RAID 0. 2nd Channel is for Transaction Logs -- it's also at RAID 0. 3rd Channel is for the data and it's a RAID 5. At a minimum you need the OS and Data on seperate channels. Keep in mind if you drop transaction logs, you are going to feel it regardless of which channel you drop to. Which is why we dedicate a channel to tlogs. We drop every hour. If you want to run the Data on a RAID 10 -- you absolutely can. We have never needed it. You will get a better performance increase from dedicating a hardware RAID channel to your data and setting it to a RAID 5 and stuffing as many disks as you can in the channel. RAID 5 performance increases significantly with each extra drive added. Hardware RAID channel being the operative word. Software RAID has no place on a database server... any server for that matter. Link to comment Share on other sites More sharing options...
SDS Posted May 8, 2010 Author Share Posted May 8, 2010 We run our database servers with three channel cards. 15k Hot-pluggable drives. 1st channel is for the OS -- it's at RAID 0. 2nd Channel is for Transaction Logs -- it's also at RAID 0. 3rd Channel is for the data and it's a RAID 5. At a minimum you need the OS and Data on seperate channels. Keep in mind if you drop transaction logs, you are going to feel it regardless of which channel you drop to. Which is why we dedicate a channel to tlogs. We drop every hour. If you want to run the Data on a RAID 10 -- you absolutely can. We have never needed it. You will get a better performance increase from dedicating a hardware RAID channel to your data and setting it to a RAID 5 and stuffing as many disks as you can in the channel. RAID 5 performance increases significantly with each extra drive added. Hardware RAID channel being the operative word. Software RAID has no place on a database server... any server for that matter. Well, let's not get goofy here. We're not running Amazon.com ya know. I'm willing to go to 4 small 15k SCSI disks. I do not know the details of the RAID controller, only that it costs more money! Link to comment Share on other sites More sharing options...
mowisc Posted May 8, 2010 Share Posted May 8, 2010 Well, let's not get goofy here. We're not running Amazon.com ya know. I'm willing to go to 4 small 15k SCSI disks. I do not know the details of the RAID controller, only that it costs more money! You are right it's all about load. I would still recommend splitting your OS and Data onto seperate RAID channels. That is sound advice regardless of load. It lays the ground work for growth and it significantly increases performance. Link to comment Share on other sites More sharing options...
mowisc Posted May 8, 2010 Share Posted May 8, 2010 Well, let's not get goofy here. We're not running Amazon.com ya know. I'm willing to go to 4 small 15k SCSI disks. I do not know the details of the RAID controller, only that it costs more money! Is this site on a colocated server? Link to comment Share on other sites More sharing options...
evilbuffalobob Posted May 8, 2010 Share Posted May 8, 2010 We should definitely upgrade our drives from the 3 and outs we've been using. Link to comment Share on other sites More sharing options...
WVUFootball29 Posted May 8, 2010 Share Posted May 8, 2010 heck could save yourself some dough and get a couple hamsters to run the disks...I think Crayonz has some friends willing to work Link to comment Share on other sites More sharing options...
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