From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stan Hoeppner Subject: Re: Incredibly poor performance of mdraid-1 with 2 SSD Samsung 840 PRO Date: Tue, 23 Apr 2013 01:01:01 -0500 Message-ID: <5176239D.6060209@hardwarefreak.com> References: <5171CBF9.9020701@redhost.ro> Reply-To: stan@hardwarefreak.com Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <5171CBF9.9020701@redhost.ro> Sender: linux-raid-owner@vger.kernel.org To: Andrei Banu Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 4/19/2013 5:58 PM, Andrei Banu wrote: > Hardware: SuperMicro 5017C-MTRF Not relevant if you're using SATA ports 0-1, but may well be if using 2-5, assuming this system isn't brand new. As I said previously, you'd see some errors in dmesg if you had port/cable issues. From: Intel=AE 6 Series Chipset and Intel=AE C200 Series Chipset Specificatio= n Update Problem: Due to a circuit design issue on Intel 6 Series Chipset and Intel C200 Series Chipset, electrical lifetime wear out may affect cloc= k distribution for SATA ports 2-5. This may manifest itself as a functional issue on SATA ports 2-5 over time. =95The electrical lifetime wear out may result in device oxide degradat= ion which over time can cause drain to gate leakage current. =95This issue has time, temperature and voltage sensitivities. Implication: The increased leakage current may result in an unstable clock and potentially functional issues on SATA ports 2-5 in the form o= f receive errors, transmit errors, and unrecognized drives. =2E.. =95SATA ports 0-1 are not affected by this design issue as they have separate clock generation circuitry. Workaround: Intel has worked with board and system manufacturers to identify and implement solutions for affected systems. =95Use only SATA ports 0-1. =95Use an add-in PCIe SATA bridge solution. Not all boards are affected by this. You'd have to check the spec revision on your C202, which means contacting SuperMicro with your boar= d revision/serial number. To be certain you're not affected simply use only ports 0-1. But on that note... It may be an opportune time to consider dropping in a LSI 9211-4i. 4GB/s raw throughput, plenty for 4 SSDs at full boogie should you expand. The kit version comes with a 1-4 breakout cable for your 1U SM chassis drive backplane. Even if we get your issue fixed via software and both drives are humming away at ~260MB/s, that nightly backup process you mentioned, and others, would surely benefit from an additional ~200MB/s throughput. --=20 Stan -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html