From: Dirk Geschke <dirk-WMiem5eIfR0n5izryJqWLw@public.gmane.org>
To: "linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
<linux-bcache-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: bcache not working on large files?
Date: Wed, 23 Oct 2013 16:47:16 +0200 [thread overview]
Message-ID: <20131023144715.GA3373@euve30603.vserver.de> (raw)
In-Reply-To: <20131022214553.GC26186-TGNR7510c4H9eX/OD4jYIkzuTB+3w3uf@public.gmane.org>
Hi all,
> So with 8 threads doing random I/O of 4k blocks in a 1000 GB file
> results in IOPS in the range of about 20,000. The same setup with
> a file of 10,000 GB results in an IOPS of about 400. That is about
> the same rate the HDDs have without bcache. This is something I did
> not expect. It looks like bcache stopped to work at all...
I have to correct it: I rebuild the SSD-RAID and used now an RAID 0
instead of RAID 6 for caching. So now I get about 10.000 IOPS with
writing 4k blocks . I think this is
a) ok
and
b) it is not a bcache problem
I suspect it is a problem of the raid controller, but I have no clue
which one...
Probably it is a better decision to use a separate raid controller
for SSD (b)cache...
Best regards
Dirk
--
+----------------------------------------------------------------------+
| Dr. Dirk Geschke / Plankensteinweg 61 / 85435 Erding |
| Telefon: 08122-559448 / Mobil: 0176-96906350 / Fax: 08122-9818106 |
| dirk-tpR6ahGJfjwEZ6m2XrtfILNAH6kLmebB@public.gmane.org / dirk-WMiem5eIfR0n5izryJqWLw@public.gmane.org / kontakt-WMiem5eIfR0n5izryJqWLw@public.gmane.org |
+----------------------------------------------------------------------+
next prev parent reply other threads:[~2013-10-23 14:47 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-22 7:08 bcache not working on large files? Dirk Geschke
[not found] ` <20131022070830.GA20286-TGNR7510c4H9eX/OD4jYIkzuTB+3w3uf@public.gmane.org>
2013-10-22 17:35 ` Rolf Fokkens
[not found] ` <5266B774.6040202-6w2rdlBuEQTpMFipWq+H6g@public.gmane.org>
2013-10-22 18:03 ` Dirk Geschke
[not found] ` <20131022180316.GA24473-TGNR7510c4H9eX/OD4jYIkzuTB+3w3uf@public.gmane.org>
2013-10-22 21:11 ` matthew patton
[not found] ` <1382476284.36900.YahooMailNeo-XYahOdtEMNlRBbKmAC7my5OW+3bF1jUfVpNB7YpNyf8@public.gmane.org>
2013-10-22 21:45 ` Dirk Geschke
[not found] ` <20131022214553.GC26186-TGNR7510c4H9eX/OD4jYIkzuTB+3w3uf@public.gmane.org>
2013-10-22 22:27 ` matthew patton
[not found] ` <1382480829.46079.YahooMailNeo-XYahOdtEMNkbWpotXP+qY5OW+3bF1jUfVpNB7YpNyf8@public.gmane.org>
2013-10-23 2:06 ` Paul B. Henson
2013-10-23 14:47 ` Dirk Geschke [this message]
2013-10-22 22:16 ` matthew patton
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