I guess I misinterpreted it , i saw it as Statment 1; "For a high-performance production virtual SQL Server instance, it's important that you put your OS files, data files, and log files on different VHDs or pass-through disks."
Statement 2: "If you're using a shared storage solution, (meaning if you are not using the server as your storage , then) it's also important that you be aware of the physical disk implementation and make sure that the disks used for the SQL Server log files are separate from the disks used for the SQL Server data files." thx for clarifying From: mich...@smithcons.com To: ntsys...@lists.myitforum.com Subject: RE: [NTSysADM] Log Files & DB on HyperV Date: Sun, 10 May 2015 15:40:47 +0000 Good article. Ok, you can’t take what Michael Otey wrote out of context. I agree with his entire paragraph, but with just the one sentence you originally quoted – I wouldn’t completely agree with it. I would say, like a good consultant, “it depends”. J Here is the entire paragraph: For a high-performance production virtual SQL Server instance, it's important that you put your OS files, data files, and log files on different VHDs or pass-through disks. If you're using a shared storage solution, it's also important that you be aware of the physical disk implementation and make sure that the disks used for the SQL Server log files are separate from the disks used for the SQL Server data files. Michael is recommending that for maximum performance you ALSO split the physical drives. For example, one RAID-10 set for OS, one RAID-10 set for data, and one RAID-10 set for logs. So if you are going to have separate VHDs for each, you also need those VHDs to be put on different physical disks. Having a VHD/VMDK for os, one for data, and one for logs – all of the same physical disk – isn’t going to improve performance. The I/O profile for each of those workloads is different. Most NAS/SAN have both a clustersize and a stripe size. The recommendation is that you continue to use a clustersize of 64K and a stripe size that is a multiple of 256K. For the most efficient stripe size for a given vendor, you need to consult the vendor documentation. From: listsadmin@lists.myitforum.com [mailto:listsadmin@lists.myitforum.com] On Behalf Of J- P Sent: Sunday, May 10, 2015 9:50 AM To: NT Subject: RE: [NTSysADM] Log Files & DB on HyperV Michael, I did you read your article , and I must say the thought of redoing all the servers makes me cringe (but i guess we gotta do what we gotta do) On that note, do you recommend the 64k on storage devices as well (synology) Here's the article i was referencing http://sqlmag.com/sql-server/sql-server-virtualization-tips Thanks From: mich...@smithcons.com To: ntsys...@lists.myitforum.com Subject: RE: [NTSysADM] Log Files & DB on HyperV Date: Sun, 10 May 2015 13:30:41 +0000 What article is that? With SQL, just as with Exchange, it’s all about IOPS. The big difference is more about clustersize than anything else, and that needs to be correct both physically and virtually. I recently wrote about this fact: http://theessentialexchange.com/blogs/michael/archive/2015/05/06/clustersize-blocksize-and-allocation-unit-size.aspx From: listsadmin@lists.myitforum.com [mailto:listsadmin@lists.myitforum.com] On Behalf Of J- P Sent: Sunday, May 10, 2015 9:25 AM To: NT Subject: RE: [NTSysADM] Log Files & DB on HyperV That was my theory /thought process as well, however, I was reading an article on sql and hyper-V (yes I know sql is not exchange but it emphasizes using seperate VHDs) "For a high-performance production virtual SQL Server instance, it's important that you put your OS files, data files, and log files on different VHDs or pass-through disks" It was this that prompted me to ask about exchange, From: charles.sulliva...@bc.edu Date: Sun, 10 May 2015 02:04:21 -0400 Subject: RE: [NTSysADM] Log Files & DB on HyperV To: ntsys...@lists.myitforum.com I’ll be interested in seeing what others have to say, but to me if the VMDKs live on the same physical data store it won’t make any difference. Even if you put them on separate data stores which have VMDKs from other VMs with high IO, that may be just as bad or worse. At VMworld last year I asked someone from VMware and he leaned toward that theory. From: listsadmin@lists.myitforum.com [mailto:listsadmin@lists.myitforum.com] On Behalf Of J- P Sent: Saturday, May 9, 2015 1:08 PM To: NT; excha...@lists.myitforum.com Subject: [NTSysADM] Log Files & DB on HyperV Hi all, I'm cross-posting this because despite it being for Exchange, it does pertain Windows as well. Back in the physical days , it was always OS, LogFiles, and DB on separate disks/volumes/arrays etc.. Now with virtulization, is it still recommended /best practice to create separate VHD's for the OS/DB/Log files for performance gain? TIA
