On May 25, 2014, at 2:38 PM, Günther Alka via illumos-discuss <[email protected]> wrote:
> Am 25.05.2014 um 23:14 schrieb Garrett D'Amore <[email protected]>: > >> IMO host protected area is a crummy hack designed to allow you to get better >> performance from a cheap consumer drive. Modern enterprise SSDs shouldn't >> need this hack. The cheap drives are cheap precisely because they lack >> sufficient internal overprovisioning. >> >> Yet one more reason not to aim for the cheapest possible solution. (There >> are actually other more important reasons but that is another topic best >> covered elsewhere.) >> >> Anyway if you need this hack you can get it by setting ZFS reservations or >> partitioning your drive. Either works without needing HPAs. >> >> I will always advocate just spend the money for a decent drive instead of >> low balling. I haven't done the math but if you think about over >> provisioning this way I think you wind up giving back a bit of your cost >> savings in a higher cost per GB as you lose that extra space. >> >> Usually the cheap drives have lower performance too. You may find that in >> such circumstances it is better to use a small number of SSDs to optimize a >> larger number of hdds. Good enterprise hdds have streaming performance not >> very unlike lower end SSDs, similar or lower costs, higher reliability, and >> a couple of SSDs and a bit of ram can do a lot to mitigate the terrible >> random workload performance from such drives. >> > > > I agree at the top end of storage solutions where you can use Intel S3700 or > similar. > > But one step below, you find extreme fast and high capacity SSDs at a > fraction of those prices but without similar spare areas. > This is ok for a vendor as most people use them for trim capable systems or > do not need best of all write performance or just look at capacity. Actually, high performance people find that trim is low performance. So it gets disabled by default. > > If one wants to build high capacity/ high performance storage and needs to > look at costs (otherwise he may buy NetApp) > he or she needs to look at overprovisioning SSDs. All enterprise-grade SSDs overprovision. It is only some of the PeeCee models that don't. > > Of course you can set reservations, but that is a pool reservation and does > notd affect a single SSD especially when a pool is unbalanced. > You can also create slices or partitions but that complicates a setup. Yep, trivial for any system administrator. > > The golden way is to simply hide a area just like the high end SSDs are doing > in firmware and use the whole remaining disk as usual. Not really. All you're doing is setting the max sector count as shown to the OS. This is more work than partitioning for the exact same functionality. > > > So for me the choice is > - create HPA on Linux/ Windows or > - hope that anyone found a solution on Solaris We've shown you several ways to achieve unused space on a disk. If you'd like, sg3_utils also purports to set the sector count and it is actually portable to more OSes than Linux. -- richard -- [email protected] +1-760-896-4422 ------------------------------------------- illumos-discuss Archives: https://www.listbox.com/member/archive/182180/=now RSS Feed: https://www.listbox.com/member/archive/rss/182180/21175430-2e6923be Modify Your Subscription: https://www.listbox.com/member/?member_id=21175430&id_secret=21175430-6a77cda4 Powered by Listbox: http://www.listbox.com
