Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Sun, Apr 01, 2012 at 02:16:42PM +0200, Arnold Krille wrote: > On Saturday 31 March 2012 15:08:59 Digimer wrote: > > On 03/31/2012 02:25 PM, Lukas Gradl wrote: > > > Am Freitag, den 30.03.2012, 12:15 -0700 schrieb Digimer: > > >> Re: RAID 1; I've used these little adapters quite a bit in production > > >> and have not had any heat problems; > > >> > > >> http://usa.chenbro.com/corporatesite/products_detail.php?sku=72 > > > > > > Thanks for that link - they look interesting. > > > > > >> SSDs are nice, but they are not enterprise class (unless you have > > >> serious money). I'd recommend looking at 2x seagate 10k or 15k SAS > > >> drives. Plug those into an LSI 9265-8i with BBU and you will likely find > > >> the performance is quite nice, without inducing the risks of running > > >> into early failure on SSDs. > > > > > > 2 LSI 6295 with BBU, 4 10k SAS drives, the mounting bays - that's around > > > 2500 EUR. > > > > > > For now the system uses two local SATA-Drives with software-raid1 and > > > this setup is more than enough performance. Is there really no cheaper > > > solution to get DRBD up and running with the same perfomance than a > > > local Software-Raid1? > > I'm not sure I understand the question, sorry. > > > > DRBD isn't much slower than the native disk performance, provided your > > network is fast enough. > > I wouldn't sign that. While 1GB-network compares to current sata disks, the > throughput isn't everything. There is also latency where the network layer in > drbd introduces a factor of ten compared to pure local disks and when using C- > protocol. How is that? SATA disk latency for random writes: >= 10ms Round trip time on GigE direct link: < 0.15 ms So wherever you see your factor 10, it is unlikely to be the "network layer in DRBD". > And when there are many users/apps accessing this resource, its the > latency that makes them complain. That is correct. -- : Lars Ellenberg : LINBIT | Your Way to High Availability : DRBD/HA support and consulting http://www.linbit.com