plockery

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  1. plockery

    Raid5 Scsi vs Sata for a terminal server

    Thanks for the input HMTK and HachavBanav. This convinces me that I am way out of my depth here. I really am just an academic acting also as a part time IT administrator in an organisation that can't afford a specialist with no more under my belt than what I have learnt fiddling with pc's and this server over a fair period of time. But this where I am at. 1. I know that not many people run an exchange server + office on the one terminal server. I know that it is not considered best practice. Until recently I thought that SBS could run in TS mode and hence could see no reason if SBS had exchange and office on the same server why we could not happily do the same. But now it seems SBS can no longer be run in TS mode for the reasons HMTK points out. 2. However, whether things are operating optimally or not, we have never had any noticeable performance problems with our server. For those who logon to the TS (we do have a couple of people who work from proper workstations/laptops) everything works well and quite fast whether that be applications, mail or database stuff. So I see no need to change this unless I have to. Greater security is not a big concern either. 3. We do however, have a space problem. Putting together another scsi raid 5 set of larger disks is expensive. So I wondered about the SATA alternative. 7200rpm Sata drives are really cheap but I suspect would give a noticeable performance hit - some people I have asked say it would, others say that practically speaking we would not notice a difference. This is one of the reasons I began this post. I think our motherboard (Tyan Thunder S2880) does have a sata raid 1 (no raid 5) controller built in but I will have to check that since I think it may be optional. The recommemded velociraptors are about 3 x the price of the 7200rpm sta drives. Hence what I am faced with is a performance vs price tradeoff and I have no expertise in knowing really how to assess this. I am relying on advice from the experts like you guys!! 4. I had not thought about raid1 before because I had assumed raid 5 would be better but from what I am reading, I gather both of you agree that raid 1 might actually give better performance for our setup than raid 5 which is a surprise. Is that correct? Thanks again for your help.
  2. plockery

    Raid5 Scsi vs Sata for a terminal server

    Thanks for the replies. Here is the information asked for. What programs do our users run? - fairly normal sort of stuff - Microsoft Office Professional 2003, Myob Premier 11 for finance and payroll, Microsoft Sql server for database, Microsoft Exchange Server 2003 for mail, specialist library software and database indexes, Microsoft visual studio 8 etc. Is this a stand alone server? Yes it is. What about backup? We backup the whole array every night to a usb external hard drive with Acronis True Image Server. We have two external hard drives and one remains off site and the two drives are swapped one a week. So do you have 100gb... ? Yes overall about 106gb at 15K in Raid 5. Now for my comments and further questions 1. I must confess my ignorance somewhat. I understand raid 5 because of use and that is what was recommended and installed when we bought the server a few years ago. Raid 1 I gather is mirrored disk pairs. I can see with the size of Sata drives why this is recommended since I could get plenty of space with say just 2 300 gb drives as Hachabanav suggests. However, for some reason I always thought that RAID 5 was much faster than RAID 1 because of the ability to write to several drives at once, whereas everything is read and written from one drive in raid 1. Am I wrong here or doesn't the performance difference matter? Is Raid 1 faster than Raid 5 or vice versa? 2. Not sure that I fully understand how Raid 1+0 works. Can you explain a bit more? What advantage is there over riad 1 alone? 3. I don't know what NT volume alignment is - never had to do it. Does it only arise with Raid 1? 4. Can I make raid 1 hot swappable? 5. Whether I use raid 1 or raid 5 what sort of performance loss is there for me to use sata instead of scsi? Would it be noticeable to the ordinary user? I presume it also makes a difference as to whether Sata is 7200rpm or 10000rpm. I could for instance buy two 300gb scsi drives - more expensive, but I already have an adaptec scsi controller and backplane? Peter
  3. I have a single server at work runing in windows server 2003 in terminal services mode for a small educational institution. There are about 25 terminals running off the server with about 18 in concurrent use in peak time and as little as 5 in non-peak times. At the moment the terminal server has dual AMD opteron processors with 2 gig ram, an adaptec 2120S raid controller and 4 x 36 gig seagate ST336753LC 15k Scsi drives in Raid 5 configuration. The problem is we are running out of space. Since I have a 5 slot backplane, the first option was to get another drive. I could no longer get one of these drives, but could get one that was simply the newer version of that drive, same capacity, speed etc. Seagate said it should work in combination with the other drives and the adaptec card is supposed to be able to take different capacity drives as well, but when I tried to add this drive to the array, it did not work - slowed down the whole array and would stall etc. I had to take it back out and go back to the original four drives. But now given our space problem, the fact that even adding one more 36 gig drive might not provide enough long term space anyway, and the low cost of Sata drives, I am wondering whether I should switch the whole system to 4 x 250 gig 7200 Sata drives with a new controller card and backplane. This would obviously give me more space than we would ever need (I could just go with 4 x 120 gig drives really). The question I have is whether there might be a very noticeable performance hit or not? (It would need to be fairly noticeable give the much lower cost and greater capacity of Sata drives.) Or is there likely to be a reliability issue? Are there any other considerations I need to think about? I have to do something about the space problem relatively soon. Any advice would be most appreciated.