On Sat, 21 Aug 2021 at 22:34, Teoman Onay <tonay@xxxxxxxxxx> wrote: > > You seem to focus only on the controller bandwith while you should also consider disk rpms. Most SATA drives runs at 7200rpm while SAS ones goes from 10k to 15k rpm which increases the number of iops. > > Sata 80 iops > Sas 10k 120iops > Sas 15k 180iops We currently have Seagate ST2000NX0433 SAS (2TB) drives and am considering getting Toshiba MG07ACA14TA 14TB 3.5-Inch LFF 6Gbps 7.2K RPM 4Kn MG07ACA Series SATA Hard Drives instead. So spin speed is the same. The SATA drives have 248 MiB/s Maximum Sustained Data Transfer Speed vs the 136MB/s of the SAS drives. The MTBF of the SAS drives is 2.5 Million hours vs the SAS's 2 million hours So on paper the new SATA drives look better than the SAS drive. Of course, that is not taking the controller and SCSI features into account. > > MBTF of SAS drives is also higher than SATA ones. > > What is your use case ? RGW ? Small or large files ? RBD ? RBD, general usage for KVM and LXC in a multi-tenant hosting environment. The Database hosting is done on NVMe SSD's and the WAL's on Intel SSD's. The I guess the question really is how import is it for ceph to an intelligent drive interface. From my limited understanding of this, it seems that the whole design of ceph is so that this doesn't really matter than much, unlike in a traditional RAID environment. > > > > On Sat, 21 Aug 2021, 19:47 Roland Giesler, <roland@xxxxxxxxxxxxxx> wrote: >> >> Hi all, >> >> (I asked this on the Proxmox forums, but I think it may be more >> appropriate here.) >> >> In your practical experience, when I choose new hardware for a >> cluster, is there any noticable difference between using SATA or SAS >> drives. I know SAS drives can have a 12Gb/s interface and I think SATA >> can only do 6Gb/s, but in my experience the drives themselves can't >> write at 12Gb/s anyway, so it makes little if any difference. >> >> I use a combination of SSD's and SAS drives in my current cluster (in >> different ceph pools), but I suspect that if I choose SATA enterprise >> class drives for this project, it will get the same level of >> performance. >> >> I think with ceph the hard error rate of drives becomes less relevant >> that if I had used some level of RAID. >> >> Also, if I go with SATA, I can use AMD Epyc processors (and I don't >> want to use a different supplier), which gives me a lot of extra cores >> per unit at a lesser price, which of course all adds up to a better >> deal in the end. >> >> I'd like to specifically hear from you what your experience is in this regard. >> _______________________________________________ >> ceph-users mailing list -- ceph-users@xxxxxxx >> To unsubscribe send an email to ceph-users-leave@xxxxxxx >> _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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