In general, the purpose of a RAID, depending on the chosen Raid level, provides a different balance among the key goals data redundancy, availability, performance and capacity. Based on the specific requirements, it is the responsibility of the storage owner to decide which balance of the various factors is the right one for the given … Read more
Okay. This is an interesting question, as there are a number of options available to you. Some concepts to clarify and understand, as they relate to this situation: Perceptions of “speed” or “fast”. RAID controller performance. SAS topology. Benchmarking a system and/or identifying bottlenecks. In order to get the maximum performance, we really need each … Read more
Marketing. 7.2K drives are slower and easier to produce, and with higher error thresholds which improves yields (and capacity). However, in terms of I/O operations each discrete disk can support, the 7.2K drives are markedly less performant than their faster brethren. Therefore they get the ‘Nearline’ moniker, as they’ll hit I/O saturation much faster than … Read more
We have had some ups and downs. Including finding our first ONTAP bug before we’d deployed and producing some certain benchmark conditions that weren’t quite what we expected. But that probably makes it sound worse than it really is. In service it has functioned very well and I wouldn’t hesitate recommending them to someone else. … Read more
QLC SSDs are absolutely inadequate for write heavy workload as databases and SAP. I strongly suggest you to buy enterprise-grade TLC disks, as Samsung PM/SM863 and Intel S4510/S4610. I would not go the SAS 10k route unless the SSD system cost too much for your budget. Finally, I would keep all disks in the same … Read more
It seems to me the problem is transferring a file before it’s complete, not that you’re deleting it. If this is Linux, it’s possible for a file to be open by process A and process B can unlink the file. There’s no error, but of course A is wasting its time. Therefore, the fact that … Read more
Interestingly, Google published a study that looked at a pretty large population of drives and their failure rates. One section says, and I quote: “In contrast to age-related results, we note that all results shown in the rest of the paper are not affected significantly by the population mix.” The authors found that drives tended … Read more
A NAS (Networked Attached Storage) is a device serving files via the network. One protocol to accomplish this is NFS. So a NAS can use the NFS protocol (or another protocol). So a Linux server providing NFS exports is, in effect, a NAS device. Is there a good reason to pick a NAS filer over … Read more
Yes, the extensive command set of the SCSI is a big bonus of using it over SATA. from SAS’ Wiki: SATA uses a command set that is based on the parallel ATA command set and then extended beyond that set to include features like native command queuing, hot-plugging, and TRIM. SAS uses the SCSI command … Read more
Uhm… iostat on my system shows the IOPS: Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn sda 1.00 64.00 0.00 64 0 Might want to look at upgrading.