When we wants to use Windows Datacenter License, its better. A big server, with a lot of things will be better. Only time you need to care about MB/s is streaming workload, pure sequential access, with one or just a few clients on the array. except with SSDs, their IOPS is so high that MB/s might actually become the bottleneck. Tho we are moving more towards large 20-24 disk arrays (md RAID5+0), with extensive use of SSDĪnd oh yeah: Most of the time you don't care about MB/s. Got to test AMD E350 for this mini size NAS as well due to ability to have 4x the ram. Tho, ATOM is far too slow when you need to move those BIG (in our case upto 6TiB) sparse image files. We get out of them roughly the raw drive performance (amazingly for RAID5). Or data sanity)īelieve or not, most of our NAS units are ATOMS with 5xSATA on RAID5, some of them have SSD cache with big expensive drives, but eventually they always end up working as a brake. (Nevermind other design issues with ZFS when it comes to performance. ZFS L2ARC SSD Cache: Warmup far too slow, in practice just single magnetic disk worth of iops on average, peaks 3 times. Most of them use LRU as the algo, which isn't very good. Least bad is EnhanceIO but DO NOT, i repeat DO NOT enable writeback cache, just writethrough. Only one we don't have hands on experience is bcache, all the others: Flashcache, EnhanceIO, ZFS L2ARC, suck big time. So it's better just to use them to get more ports and do a softraid for performance, management is a bit nastier etc.Īlso HW RAID gives nice things such as Writeback cache w/ BBU, that gives a decent boost. In our experience tho, we've never come even close with HW RAID in terms of performance than with software. If you do HW RAID, make sure you get a decent controller, because that dictates your performance. All RAID loose % of the raw HW performance, if you want to get as close to HW perf as possible, and you can easily partition the data, then just have individual drives, no raid etc., and make so that you can serve requests from the backup as well (get all the perf you can on your budget) if possible for your workload. If you are like us, you will do well with RAID10/50. Ofc, all depends on your usage, your dataset etc. WD Velociraptor seems a nice trade off, but no experience here as our workload either is very high performance small datasets, or "low" performance large datasets. SAS 10k, 15k -> Expensive, and slow per €, only time they are good if you have a severe limitation on quantity of disks, otherwise get same value worth of SATA drives -> More IOPS (what you really want) and more capacity, in exchange for some more failures. Just make sure that your SSD is fast enough, put aside 15% of the space for firmware wear leveling algos (otherwise you need to secure erase like daily to restore performance) and you have enough of it compared to storage -> otherwise the SSD will become bottleneck because how "caching" software has been done. That being said, many have had good experiences with bcache. Most SSD caching software absolutely sucks, insanely bad. We deal mainly with storage performance - on the budget, since our specialty is on data delivery, IO perf is the most important one for that. Or if I have OS installed on this SSD, this can't be used to do the cache? How to do it? First Install CentOS on the SSD and after config ZFS or Fastcache or Bcache? Some one says to use FastCache, other says to use Bcache, and others says to use ZFS. Tried to find some tutorial about this, but very confused. Wold like to use the second option because I can use a local drive to do snapshots backups / restore.įor the first option, I know how it works, but for the second option, I really don't know how to do it. I see that some guys says the MB/s is not important, and the important is the IOPs. I'm able to have this on the second option? The first option 4x2tb-raid10, I know the results, if you:ĭd if=/dev/zero of=test bs=64k count=16k conv=fdatasync What is the best option? This will be used to host KVM and Openvz VPSs and these VPSs will host websites (cPanel / Virtualmin).ī)2 X 3TB Software Raid 1 / 1 X SSD ?GB (Cache?) / 1 X 1TB for Backups I'm getting a new server with max 4x drive and no hardware Raid options.
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