RAID1 vs RAID10?
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From: Paul Hutchings on 12 Jan 2006 16:58 I'm planning on getting an ML370 to support approx 600 mailboxes (huge variation of size and usage profiles). I was planning on this: 2 x 72gb 15k SCSI hardware RAID1 on Channel A partitioned for OS + Logs 4 x 146gb 10k SCSI hardware RAID10 on Channel B for first storage group and database (still reading up but can't envisage more than 1 SG/database). 1 x 146gb 10k SCSI hot-spare. 1 x 300gb 10k SCSI spindle for NT backup to disk (to then be streamed to tape). I wanted some opinions/thoughts on whether I would be better off considering: 2 x 36gb 15k SCSI hardware RAID1 on Channel A for OS 2 x 36gb 15k SCSI hardware RAID1 on Channel B for Logs 2 x 146gb 10k SCSI hardware RAID1 on Channel B for first storage group and database (seems MS now say RAID1 over RAID5). 1 x 146gb 10k SCSI hot-spare. 1 x 300gb 10k SCSI spindle for backup The server will likely be a dual 3.4ghz 2mb cache Xeon with 4gb RAM. I'm aiming to avoid an external storage cabinet for now, but this way the option is still there in the future if needed. Basically I've been reading way too much and I suspect I'm getting a little "performance paranoid" where for our sort of usage either will do the job. cheers, Paul -- paul(a)spamcop.net
From: Mark Arnold [MVP] on 12 Jan 2006 17:19 On Thu, 12 Jan 2006 21:58:36 +0000, Paul Hutchings <paul(a)spamcop.net> wrote: >I'm planning on getting an ML370 to support approx 600 mailboxes (huge >variation of size and usage profiles). > >I was planning on this: > >2 x 72gb 15k SCSI hardware RAID1 on Channel A partitioned for OS + Logs >4 x 146gb 10k SCSI hardware RAID10 on Channel B for first storage group >and database (still reading up but can't envisage more than 1 >SG/database). >1 x 146gb 10k SCSI hot-spare. >1 x 300gb 10k SCSI spindle for NT backup to disk (to then be streamed to >tape). > >I wanted some opinions/thoughts on whether I would be better off >considering: > >2 x 36gb 15k SCSI hardware RAID1 on Channel A for OS >2 x 36gb 15k SCSI hardware RAID1 on Channel B for Logs >2 x 146gb 10k SCSI hardware RAID1 on Channel B for first storage group >and database (seems MS now say RAID1 over RAID5). >1 x 146gb 10k SCSI hot-spare. >1 x 300gb 10k SCSI spindle for backup > >The server will likely be a dual 3.4ghz 2mb cache Xeon with 4gb RAM. > >I'm aiming to avoid an external storage cabinet for now, but this way >the option is still there in the future if needed. > >Basically I've been reading way too much and I suspect I'm getting a >little "performance paranoid" where for our sort of usage either will do >the job. > >cheers, >Paul You can't do RAID10 on the 370 without external storage, there wouldn't be enough slots. The 370 is fine for a departmental box. Use a pair for the OS, a pair for the Exchange binaries and logs and then the 3rd pair for the stores. You wouldn't need to worry about a hot spare. Use a large set of disks for the logs and store the backup on that set and spool it off to tape.
From: John Fullbright on 12 Jan 2006 17:37 You really haven't given any indication of what the expected load is. If you read the WP "Optimizing storage for Exchange 2003", use the section on determining performance requirements from environmental data. I do storage sizing for Exchange day in and day out, and have to say that the assumtions for light medium and heavy users have never even been close in the literally hundreds of environments I've been in. Speaking from experience, it's always better to measure than assume. Once you figure out the IOPS/user, you can calculate the storage perfomance requirement for the number of users you have in your environment Don't forget to add IOPS for backup/replication. Add IOPS as well for the location of your SMTP directories. For 10K RPM SCSI drives you can use 85 IOPS per spindle for a target 20ms IO. The referenced paper gives the formulas for calculating the write penalty; don't forget to add that in as well. On storage group design, it really comes down to attachments, log files, and log buffers. Each storage group has a seperate set of logs, so multiple storage groups is one way you can partition disk activity to the log files. Log buffers are set at the storage group level, with a max 9000 for E2K3 SP1. Log buffers are important if you have many large attachments flowing through your system. You increase the number of log buffers to reduce the occurance of log stalls. When the log buffers reach the high water mark (95%) there is a forced commit to disk until the low water mark is reached. During this time, Client IO activity is quiesed, resulting in the "Requesting Data" dialog appearing simultaniously on the outlook client of all users connected to the storage group. It's clearly something you want to avoid. Many times you add additional storage groups to allow more log buffers. Log buffers are set on a per storage group basis. The current MS recommendation is to start with 4 storage groups, even if there is only one database in each storage group. Before formatting your LUNs, you may want to experiment with disk alignment. When a LUN is presented to WIndows, the first 63 sectors are used for partition data. The first partition begins at the 64th sector. In the old days, when disks had 64 sectors on each track, you could get a performance increase by causing the start of the first partition to begin on the first sector of the second track. Nowadays, with virtualization layers abstracting the physical architecture, it's difficult to say if you will gain anything by disk alignment. You'll have to try it out and see. When formatting a LUN, choose an appropriate allocation unit size. For the location of the EDB file, 4k. The stm file can be a bit higher, around 8k average and up to 32K, but it really depends on the type of client that will be accessing mailboxes. Unless in a POP/IMAP heavy environment 4K will likely do. Log writes can be anywhere from 512 bytes to 90% of the number of log buffers /2 K. It depends if the write was a lazy commit or a forced commit. In may cases, 4K is fine. If you have a lot of large messages flowing through the system, you may want to go larger. The location of the SMTP quese should use an allocation unit size of roughly the average message size going through the smtp virtual server. RAID 1 and RAID 10 are good chioices and are indeed the current MS recommendation. This should get you started "Paul Hutchings" <paul(a)spamcop.net> wrote in message news:paul-EFCC7A.21583512012006(a)msnews.microsoft.com... > I'm planning on getting an ML370 to support approx 600 mailboxes (huge > variation of size and usage profiles). > > I was planning on this: > > 2 x 72gb 15k SCSI hardware RAID1 on Channel A partitioned for OS + Logs > 4 x 146gb 10k SCSI hardware RAID10 on Channel B for first storage group > and database (still reading up but can't envisage more than 1 > SG/database). > 1 x 146gb 10k SCSI hot-spare. > 1 x 300gb 10k SCSI spindle for NT backup to disk (to then be streamed to > tape). > > I wanted some opinions/thoughts on whether I would be better off > considering: > > 2 x 36gb 15k SCSI hardware RAID1 on Channel A for OS > 2 x 36gb 15k SCSI hardware RAID1 on Channel B for Logs > 2 x 146gb 10k SCSI hardware RAID1 on Channel B for first storage group > and database (seems MS now say RAID1 over RAID5). > 1 x 146gb 10k SCSI hot-spare. > 1 x 300gb 10k SCSI spindle for backup > > The server will likely be a dual 3.4ghz 2mb cache Xeon with 4gb RAM. > > I'm aiming to avoid an external storage cabinet for now, but this way > the option is still there in the future if needed. > > Basically I've been reading way too much and I suspect I'm getting a > little "performance paranoid" where for our sort of usage either will do > the job. > > cheers, > Paul > -- > paul(a)spamcop.net
From: Hank Arnold on 13 Jan 2006 04:50 Sure you can.... There is a cage that can be added that will convert the 2 external drive bays into a 3rd RAID array. It will require that the bays be empty and adding at least one more RAID adapter. We configured this for our 2 ML370 servers until we decided to go with new hardware..... -- Regards, Hank Arnold "Mark Arnold [MVP]" <mark(a)mvps.org> wrote in message news:d9lds111fa5ucdubr8q0e4v5dtaogp5a2s(a)4ax.com... > > You can't do RAID10 on the 370 without external storage, there > wouldn't be enough slots.
From: Hank Arnold on 13 Jan 2006 04:59
I like the second proposal better if you dump the "hot spare" and go with RAID 5. Actually, what I would do is dump the 300GB drive and add another 146GB drive. Make the configuration 2 x 72GB RAID 1 OS 2 x 146GB RAID 1 Logs 4 x 146GB RAID 10 Databases (or RAID 5 w/ hot spare) This assumes that there is room for the NTBACKUP file somewhere on one of the drives or putting it somewhere on another network drive.... As others have said, this is hard to specify w/o doing an analysis of usage. Check out MS articles. Also, look for some Exchange configurators (I believe Dell has one) that will walk you through the anticipated setup and usage and recommend hardware.... -- Regards, Hank Arnold "Paul Hutchings" <paul(a)spamcop.net> wrote in message news:paul-EFCC7A.21583512012006(a)msnews.microsoft.com... > I'm planning on getting an ML370 to support approx 600 mailboxes (huge > variation of size and usage profiles). > > I was planning on this: > > 2 x 72gb 15k SCSI hardware RAID1 on Channel A partitioned for OS + Logs > 4 x 146gb 10k SCSI hardware RAID10 on Channel B for first storage group > and database (still reading up but can't envisage more than 1 > SG/database). > 1 x 146gb 10k SCSI hot-spare. > 1 x 300gb 10k SCSI spindle for NT backup to disk (to then be streamed to > tape). > > I wanted some opinions/thoughts on whether I would be better off > considering: > > 2 x 36gb 15k SCSI hardware RAID1 on Channel A for OS > 2 x 36gb 15k SCSI hardware RAID1 on Channel B for Logs > 2 x 146gb 10k SCSI hardware RAID1 on Channel B for first storage group > and database (seems MS now say RAID1 over RAID5). > 1 x 146gb 10k SCSI hot-spare. > 1 x 300gb 10k SCSI spindle for backup > > The server will likely be a dual 3.4ghz 2mb cache Xeon with 4gb RAM. > > I'm aiming to avoid an external storage cabinet for now, but this way > the option is still there in the future if needed. > > Basically I've been reading way too much and I suspect I'm getting a > little "performance paranoid" where for our sort of usage either will do > the job. > > cheers, > Paul > -- > paul(a)spamcop.net |